Used Measuring Stand for sale (14,232)

Condition: like new (used), Tool measuring stand for measuring tool radius and height. Measurements can be read of digital read-outs. Technical details Tool diameter min - 100mm Tool diameter max - 300mm Tool length maximum - 330mm 220v - 50hz Weight - 180 kg Supplied with operating instructions. Pedpfjyl Rnbox Aphsgr

Year of construction: 2001, condition: excellent (used), Technical Data Manufacturer: ZEISS / Stiefelmayer Type: SMM C Year of Manufacture: 2001 Measuring Range X = 12,000 mm Y = 2 x 1,400 mm Podpfeiwurcex Aphogr Z = 2,100 mm Measurement uncertainty U3 = (50 + L/40) µm

Condition: not inspected (used), Year of construction: 2008, functionality: unexamined, machine/vehicle number: 71257, No minimum price – guaranteed sale to the highest bidder! TECHNICAL DETAILS Measuring volume: 3,000 mm Accuracy: 0.07 mm MACHINE DETAILS Dimensions & Weight Installation dimensions L x W x H: 1,000 x 500 x 1,000 Weight: 30 kg SCOPE OF DELIVERY Laptop and software (completeness not guaranteed) Pgsdpfjzhuyljx Apher Transport case Note: The red base on which the laptop is placed is not included in the offer.

Condition: used, This listing is for the Partical Measuring Systems LASAIR lll 310c particle measuring systems The unit is in full working condition and is ready for immediate release The Lasair® III 310C is a state-of-the-art portable aerosol particle counter designed to meet the stringent requirements of highly regulated environments. Manufactured by Particle Measuring Systems (PMS), it sets the standard for portable particle counters, ensuring that your environment remains clean and compliant.​ Key Features Particle Size Range: 0.3 to 25.0 µm Flow Rate: 1.0 CFM (28.3 LPM) ±5% Counting Efficiency: Complies with ISO 21501-4 requirements Display: 8.4" color VGA IR touch screen (IP65 rated) Data Storage: Up to 3,000 complete data sets Connectivity: Ethernet, Modbus TCP/IP, RS-232, USB data downloading; optional wireless Ethernet Pgjdoxv A T Nopfx Apher Environmental Inputs: Four 4-20 mA inputs for external sensors Power Options: Operates on AC power or hot-swappable batteries Compliance: Meets ISO 14644-1, EU GMP Annex 1, and ISO 21501-4 standards Software Compatibility: Supports FacilityNet, PharmaceuticalNet, and FacilityPro for data analysis and reporting Reporting Capabilities: Cleanroom certification results are available through a local printout, downloadable via USB in a secure format, or through the use of external software packages Wireless Communication: Wireless network communications are facilitated with an externally mounted wireless adapter, simplifying communications with network systems ​ Specifications Dimensions: 30.1 x 32.7 x 25.9 cm Weight: 6 kg (without battery), 7.5 kg (with two optional batteries) Operating Environment: Temperature: 0 – 30°C; Humidity: 5 – 95% RH non-condensing Sample Tubing: Supports 3/8", 1/2", and 3/4" tubing up to 8 meters in length Sample Output Filtering: Internally filtered to >99.97% at 0.3 µm

Condition: ready for operation (used), Year of construction: 2012, functionality: fully functional, machine/vehicle number: 7525SE-0949-FA, measuring range X-axis: 2,600 mm, number of axes: 7, TECHNICAL DETAILS Axes: 7 Measuring range: 2.6 m Accuracy Acceptance temperature: 20 °C Humidity during acceptance: 50 % Permissible single-point deviation: 0.028 mm Determined single-point deviation: 0.010 mm Maximum permissible volumetric length measuring deviation: ± 0.039 mm Determined volumetric length measuring deviation: -0.018 mm Scanner Manufacturer: Hexagon Model: CMS108 Integration: Calibrated within the measuring arm Note: Can be used on the measuring arm with appropriate scanning software Note: Scanning software not included in the scope of delivery MACHINE DETAILS Design: Portable measuring system Weight of measuring system including transport case: approx. 40 kg External dimensions of transport case for measuring arm: approx. 1,350 x 550 x 350 mm Dimensions of tripod: approx. 750 x 750 x 750 mm Weight of tripod: approx. 75 kg Dimensions of scanner case: approx. 600 x 450 x 220 mm Weight of scanner including carrying case: approx. 6 kg Notebook size: 17 inches Note: The measuring arm was relabeled before the last calibration. EQUIPMENT - Hexagon ROMER Absolute Arm RA-7525SE measuring arm, 7-axis - Mobility Pack FP2-1503-FA with wireless computer connection - Transport case for measuring arm - Magnetic base - Test bar, length 700 mm - Test sphere, diameter 25 mm - Probe box with 3 probes - Probe with ruby ball, diameter 6 mm - Probe with ruby ball, diameter 3 mm - Calibration sphere, diameter 15 mm - Dust cover - Complete cable set - Calibration certificate for measuring arm, notebook Dell M6600 - PowerInspect 11 software including hardware dongle - Hexagon RDS software - Brunson 231 roll stand, height-adjustable - Height adjustment range of tripod: approx. 700 to 1,100 mm - Scanner Hexagon CMS108 - Carrying case for scanner - Calibration certificate for scanner Note: PowerInspect 11 is exclusively for tactile measurements and cannot be linked with a scanner. Podpozv Rhuofx Aphogr Note for packaging request: €250 for special pallet with cardboard construction and tripod on a Euro pallet.

Condition: new, Year of construction: 2026, functionality: fully functional, number of drawers: 30, warranty duration: 12 months, Our company (EXPOGLASS®) manufactures machines, glass racks for the glass industry. Our offer includes a 321 x 255 pull-out glass rack. New product on request. Technical data : Number of drawers - 30 Size of panes - 2550 X 3210 for storage Load capacity of a single drawer - 1500 kg Loading space width - 80 mm Total storage width - 4460 mm Orientation (tilt side of drawers) - universal (depends on assembly) Number of positioning rollers per drawer - 8, bearing-mounted Construction - modular (combinable) Material of the front wheel of the drawer - floor friendly polyamide Rear wheel of drawer - steel - turned, bearing-mounted, with double flange, running on steel track We export our products all over the world. Psdpfoh Uudvex Aphjgr

Condition: used, 3-D coordinate measuring machine ZEISS NUMEREX - non-functional Pgsdpsfy U Ewjfx Aphjr Granite measuring table, granite measuring plate, measuring table Model No. 3648-18, Serial No. X-1019, Year of manufacture approx. 1986 Measuring range X = approx. 1250 mm, Y = approx. 900 mm, Z = approx. 400 mm Measuring plate L x W 1525 x 1435 mm Usable area 1525 x 1100 mm Measuring plate thickness 305 mm Passage width in the portal 1100 mm Measuring probe mount Ø 9.5 mm Compressed air connection 6 bar Mains connection 230 Volt, 50 Hz - Granite plate with steel inserts with internal thread - Axis adjustment with pneumatic sliding guide for X, Y and Z axis - Plate on substructure with 5 adjustable feet, 3 support plates for the adjustable feet - Computer and software missing (not included and not part of the scope of delivery) → non-functional! Space requirement of the measuring machine L x W x H 1600 x 1850 x 2200 mm Weight of the machine approx. 2.8 tons Plate damaged on one side, see picture, otherwise in good condition.

Condition: new, functionality: fully functional, warranty duration: 24 months, input voltage: 240 V, measuring range X-axis: 280 mm, measuring range Z-axis: 350 mm, overall weight: 100 kg, workpiece weight (max.): 50 kg, Equipment: type plate available, High-end contour and roughness measuring system with air-bearing motion axes, up/down measuring function and X-sensing. Anytime optionally via software updatable functions: - Motorized Y-Supporting table Scope of supply: - Basic mechanics with integrated Y-adjustment table - Integrated control system - integrated gauging force regulation - software option roughness - Software option for measurement and evaluation of the following standards: DIN EN ISO 4287 (10/1998) DIN EN ISO 4288 (04/1998) DIN EN ISO 11562 (04/1998) DIN EN ISO 13565-1 (04/1998) DIN EN ISO 13565-2 (04/1998) VDA 2006 (07/2002) Stahl-Eisen-Prüfblatt (SEP 1940) - PC W11/64Bit; 24"TFT flat screen; - Compressed air unit consisting: Particulate filter 25µm/0.1µm, oil filters and water separator 2 precision pressure regulator mounted on base with stand Podewzlcaopfx Aphogr - ConturoMatic Software; user manual - Software add-on for roughness calculation - Cable set - Protective cover, sturdy and water repellent (material), Commodity-Code 63079098 Description of the up down function: The scanning of surfaces in two directions is possible by the measuring direction switching function. This can be assessed without loss of the relationship to other scans from the same measuring process. Inside and external scans can be calculated to each other. This function is suitable without restrictions in automatic measurement programs. Additional evaluation possibilities are for example - Raceway diameters - Diameter - Thickness variation - Parallelism - Cone angle measurement - Calculation of pitch deviation - Thread testing (thread calculation software optionally) etc. Technical data contour and roughness measurement: Aerostatic linear bearings (X and Z) Measuring range Contour 360mmx550mm (X/Z) Measuring range Roughness 360mmx550mm (X/Z) Suitable range Ra Ra from 0.08µm* Suitable range Rz Rz from 0.8µm* Resolution 1nm Sensing system optically incremental 1 point measuring in X direction (static) Accuracy +/-(0.85µm+L/100)µm* [L=mm] Measuring speed contour 0.1-3mm/s self-optimizing Measuring speed roughness 0.1-0,5mm/s self-optimizing Positioning speed up to 25mm/s Probing force contour 30mN Probing force roughness 7.5mN Table load 25kg weight: 96kg * According to our specified terms- Subject to change without notice

Condition: good (used), Inspection table / Measuring table Manufacturer: STOLLE Tabletop dimensions: (mm) 3,000 x 3,000 x 350 Accuracy class 1 Pjdpfszwpucex Aphogr Tolerance 0.04 mm Plate weight approx. 6,100 kg Equipped with 13 legs for leveling.

Condition: good (used), HARTGESTEIN measuring and control plate DIN 876/1 with substructure Dimensions: Length: 800 mm Width: 600 mm Thickness: 120 mm Height with substructure: 890 mm Accuracy: DIN 876/1 Podozati Rjpfx Aphogr

Condition: excellent (used), machine/vehicle number: 94681, ZEISS PRISMO 5 3D coordinate measuring machine with VAST probing system Pgodszwvk Repfx Aphor For sale is a used ZEISS PRISMO 5 3D coordinate measuring machine, serial number 94681. The machine is equipped with a ZEISS-VAST probing system and a comprehensive multi-probe changer. A machine-side ZEISS control console is also included. Additionally available is a cabinet with probes, which is not included in the stated machine price and can be offered separately if desired. Details regarding the content and scope of the probe inventory can be provided upon request. Machine data Manufacturer: ZEISS Model: PRISMO 5 Serial number: 94681 Probing system: ZEISS VAST Equipment: Multi-probe changer Condition: used ZEISS service and inspection marking The machine has a marking from the technical service department of Carl Zeiss IQS Deutschland GmbH, referring to an inspection according to DIN EN ISO 10360. Documented specifications: MPE(E0): 2.70 + L/250 P: 2.00 RONt: 4.40 Type: PRISMO 5 Serial number: 94681 Calibration date: 02/2025 The values stated are reproduced according to the ZEISS marking on the machine. ZEISS CALYPSO 5.8 is visible on the existing control PC. The exact scope of the license or the transferability of an existing software license is not part of this information and can be checked separately if desired. Optionally available In addition, there is the possibility of purchasing a separate cabinet with a comprehensive inventory of ZEISS probes and accessories. This cabinet is not included in the machine price and can be offered separately if desired. Condition and inspection The machine is in used condition. An inspection is possible after prior arrangement. The exact scope of delivery can be agreed upon or checked based on the available components if there is concrete interest. Errors, changes and prior sale are subject to change. HOLZHÄUER Hydraulik & Maschinenbau GmbH

Condition: excellent (used), Year of construction: 2000, functionality: fully functional, machine/vehicle number: 111288, measuring range X-axis: 700 mm, measuring range Y-axis: 900 mm, measuring range Z-axis: 500 mm, workpiece weight (max.): 1,200 kg, total height: 2,930 mm, type of input current: AC, total width: 1,525 mm, total length: 1,740 mm, overall weight: 3,500 kg, table width: 925 mm, table height: 720 mm, table length: 1,195 mm, table load: 1,200 kg, compressed air connection: 6 bar, ambient temperature (max.): 35 °C, ambient temperature (min.): 10 °C, Equipment: type plate available, # Advertisement Description – ZEISS MPS PRISMO 7/9/5 For sale is a used ZEISS MPS PRISMO 7/9/5 3D coordinate measuring machine. The machine was manufactured in 2000 and has the serial number 111288. It is equipped with a ZEISS VAST probing system and a multi-probe changer. # Technical Data * Manufacturer: ZEISS * Model: MPS PRISMO 7/9/5 * Series: PRISMO * Year of Manufacture: 2000 * Serial Number: 111288 * Measuring Range X-axis: 700 mm * Measuring Range Y-axis: 900 mm * Measuring Range Z-axis: 500 mm * Probing System: ZEISS VAST * Multi-probe changer included * Machine-mounted operator console included * Condition: used # Optional In addition to the machine, it is possible to purchase a separate cabinet with an extensive collection of ZEISS probes and accessories. The cabinet is not included in the stated machine price and can be offered separately if desired. Details regarding the content and scope of the probe collection can be provided upon request. # ZEISS Service and Test Label The machine has a label from the technical service department of Carl Zeiss IQS Deutschland GmbH, referring to a test performed according to DIN EN ISO 10360. Pedpfx Ajzwu Alephogr The following values are indicated on the label: * MPE(E0): 1.40 + L/350 * P: 1.20 * THP: 1.40 * TAU: 29.00 * Type: PRISMO * Serial Number: 111288 * Label: 2025-10 The stated values are reproduced according to the ZEISS label on the machine. # Condition and Inspection The machine is in used condition. An inspection is possible by prior arrangement. Subject to errors, changes, and prior sale. HOLZHÄUER Hydraulik & Maschinenbau GmbH

Condition: used, Technical details: x-axis: 1000 mm z-axis: 600 mm diameter: - mm measuring range Y-axis: 972 mm interface: RS-232 tool taper: - weight: 40 kg power consumption: 100 Watt Floor Space WxD: 1,2 x 0,8 m Mitutoyo Linear Height 600 Height Gauge with Wenzel Precision Granite Surface Plate (Optional) The granite surface plate is not included in the sale but can be purchased separately. For sale is a high-quality Mitutoyo Linear Height 600 digital height gauge, designed for accurate 2D measurement tasks in quality control, toolmaking, manufacturing and inspection departments. Mitutoyo Linear Height 600 ·Precision digital height measuring instrument ·Measuring range: 600 mm ·RS232 data output ·Made in Japan ·High accuracy and repeatability ·Ideal for quality assurance and manufacturing environments Measurement Capabilities Psdpfx Aszbqypsphsgr ·Height measurements ·Internal and external dimensions ·Hole center distances ·Center point determination ·Step measurements ·Diameter measurements ·2D measurement applications ·Angle measurements (with optional accessories) Optional: Wenzel Precision Granite Surface Plate ·Size: 1000 × 630 mm ·Manufacturer: Wenzel Precision ·Inspection date: 07.11.1989 ·Permissible flatness deviation: 0.008 mm ·Measured flatness deviation: 0.005 mm ·Weight: approx. 280 kg An excellent solution for toolrooms, quality control laboratories, precision engineering and manufacturing facilities. *

Condition: used, Technical details: Length: 1000 mm Pgedpfx Apszb Ux Ashsr width: 630 mm height: 150 mm height over floor: 890 mm weight of the machine approx.: 250 kg space requirements of the machine approx.: 2,5 m x 2,2 m m WENZEL Precision Granite Surface Plate 1000 × 630 mm WENZEL granite surface plate 1000 × 630 mm with minor edge chips and signs of use (see photos). A WENZEL granite surface plate measuring 1000 × 630 mm (typically approx. 150 mm thick) is a high-precision inspection and measuring surface made from natural hard stone (granite). WENZEL Metrology is internationally recognized for manufacturing extremely stable, low-distortion granite surface plates used as stress-free reference surfaces in metrology laboratories, quality control departments, toolrooms, and precision manufacturing environments. *

Condition: used, Year of construction: 2003, Swiveling, but not tilting. Saw blade diameter: 550 mm. Bore diameter: 50 mm. Speed: 2800 rpm. Motor with brake: 3.0 kW. Cutting width at 90°: 420 mm. Cutting width at 45° (swiveled): 295 mm. Cutting height at 90°: 200 mm. Weight: approximately 330 kg. Pedpfxezd Tikj Aphjgr Storage location: Nattheim.

Condition: excellent (used), Year of construction: 2009, 3D coordinate measuring machine Measuring range X/Y/Z: 440 x 500 x 410 mm Pedpfx Apjzvhrdohegr Measuring uncertainty X/Y/Z: 2.5 + 3.9L/1000 µm Maximum table load: 227 kg Total weight: 293 kg

Condition: like new (used), Year of construction: 2018, functionality: fully functional, machine/vehicle number: ZEISS Comet®LƎD 8M, workpiece weight (max.): 5,000 kg, workpiece length (max.): 1,000 mm, workpiece height (max.): 1,000 mm, workpiece width (max.): 1,000 mm, ZEISS Comet®LƎD 8M Pgodpfx Apjzwk Nbehjr

Condition: excellent (used), functionality: fully functional, repeat accuracy: 0.001 mm, feed length X-axis: 1,000 mm, feed length Y-axis: 1,000 mm, feed length Z-axis: 800 mm, Equipment: documentation/manual, Measurement sensor: TP200 Software: Camio Volumetric accuracy: 2.5+L/225 µm The LK Metrology G90C is a high-precision coordinate measuring machine (CMM) ideal for industries requiring exceptional accuracy. It features a ceramic structure, air bearings, and an advanced drive system, ensuring stability and speed. The device has been thoroughly tested and inspected by our technicians and is currently available in our showroom. Pjdezwvlzopfx Aphogr For more information: nenad.mitrakovic(at)teximp.com

Condition: used, machine/vehicle number: 7F001-7, Optical multi-sensor measuring machine HEXAGON OPTIV CLASSIC 321 GL tp Year of manufacture: probably 2015 Machine number: 7F001-7 Availability: Immediately (by arrangement) Payment terms: Prepayment - by bank transfer Internal No.: OCU2 Can be inspected while powered on: YES Technical data: Metrology software: PC-DMIS Vision Vision sensor for non-contact measurement of smallest and precise components CCD camera with 6.5x motorized CNC zoom DC servo motors Modular probe changer: TESASTAR Linear guides in all axes Coaxial LED top light (white LED) LED back light (green LED + diffuser) Multi-segment LED ring light Maximum feed rate in the X, Y, Z axis: 160 mm/s Maximum workpiece weight: 20 kg Measuring resolution: 0.05 µm Measuring accuracy in the X, Y axis (optical sensor): Ex, Ey = (1.6 + L/250) µm Measuring accuracy in the XY axis (optical sensor): Exy = (2.0 + L/250) µm Measuring accuracy in the Z axis (optical sensor): Ez = (3.9 + L/200) µm Measuring accuracy in the X, Y axis (scanning probe system): Ex, Ey = (2.0 + L/250) µm Measuring accuracy in the XY axis (scanning probe system): Exy = (2.5 + L/250) µm Measuring accuracy in the Z axis (scanning probe system): Ez = (2.9 + L/200) µm Measuring volume optical sensor X 300 mm Y 200 mm Z 150 mm Measuring volume tactile sensor X 230 mm Y 200 mm Z 150 mm Scope of supply: - As shown in the pictures Note: The rolling shutter cabinet on which the PC is placed is not included in the scope of supply. Dimensions & weights: Installation dimensions L x W x H approx.: 705 x 986 x 890 mm Weight approx.: 170 kg Pgjdpfx Apozk I T Rjher ⚠️Additional notes: ►The goods are sold with exclusion of any warranty ►Technical data without guarantee ►Subject to prior sale ❗The sale of the goods is exclusively to business customers❗

Condition: like new (used), Year of construction: 2019, functionality: fully functional, Zoller Titan tool measuring machine: - Year of manufacture: 2019 - Software: titan/pilot 3.0 Pgedpfx Apozd Acajher - Max. tool length (Z-axis) = 550 mm - Max. tool diameter = 260 mm - Tool holder: SK40, KSK63, etc., as required

Condition: used, Year of construction: 2022, functionality: fully functional, input voltage: 230 V, total width: 996 mm, total length: 1,311 mm, total height: 2,633 mm, overall weight: 250 kg, input frequency: 50 Hz, Equipment: documentation/manual, The InspecVision Planar P70.20 is a high-speed, non-contact 2D optical measurement and reverse-engineering system. Machine type: 2D optical inspection and measurement system Maximum part length: 1,000 mm Maximum part width: 667 mm Maximum part thickness/height: Up to 350 mm* Maximum part weight: 50 kg, evenly distributed Measurement accuracy – length/width: ±20 / ±40 µm Point spacing / resolution: 0.18 mm Measurement speed: Less than 0.25 seconds SurfScan resolution: 0.15 mm Camera: High-resolution industrial camera Lighting: LED Software: InspecVision inspection, SPC, reporting, and reverse-engineering software CAD comparison: DXF comparison and dimensional inspection Reverse engineering: Available Power supply: 230 V, single phase, 50 Hz Psdpfxezvxg Es Aphjgr Maximum power consumption: Approx. 4 A Operating temperature: 10–30 °C Computer interface: USB 2.0 / USB 3.0 Approximate machine dimensions (W × D × H): 1,311 × 996 × 2,633 mm Machine weight: Less than 250 kg

Condition: ready for operation (used), Year of construction: 2008, functionality: fully functional, machine/vehicle number: 200008301032, measuring range X-axis: 400 mm, measuring range Y-axis: 500 mm, measuring range Z-axis: 350 mm, table width: 680 mm, table length: 855 mm, No minimum price – guaranteed sale to the highest bidder! Submitting a bid obligates you to collect the item on time between October 7, 2026, and October 14, 2026! TECHNICAL DETAILS Podpfxszu Ixuo Aphogr Measuring range, X-axis: 400 mm Measuring range, Y-axis: 500 mm Measuring range, Z-axis: 350 mm Maximum workpiece weight: 280 kg Table width: 680 mm Table length: 855 mm MACHINE DETAILS Dimensions & Weight Dimensions (L x W x H): 2,000 x 1,100 x 1,100 mm Total weight: 500 kg

Condition: excellent (used), I am offering for sale a professional LeCroy WaveJet 354A digital oscilloscope, designed for laboratory, service, and industrial applications. This is a high-quality measuring instrument with a bandwidth of 500 MHz and a sampling rate of 2 GS/s. Technical specifications: • Manufacturer: LeCroy • Model: WaveJet 354A • Bandwidth: 500 MHz • Sampling rate: 2 GS/s • 4 analog channels • USB port • Built-in carrying handle • Power supply: 90–264 V AC, 47–63 Hz Condition: • Used, in good visual condition with normal signs of use. • The device powers on and functions correctly – the display is working, as can be seen in the photos. Podpfozru Siox Aphegr

Condition: excellent (used), I am offering for sale a professional HBM MGCplus measuring system from Hottinger Baldwin Messtechnik (HBM). This is a high-end, modular measuring amplifier used in research laboratories, industry, and testing stations for signal acquisition and analysis from sensors. The device is equipped with a control panel with an LCD display and installed measuring modules. The unit being sold was removed from an industrial installation. Specifications: Pgodpfx Apezru Rrjher • Manufacturer: HBM – Hottinger Baldwin Messtechnik • Model: MGCplus • Control unit: AB22A • Installed modules: ML60B BL01 (2 units) AP17 SY03 • Power supply: 115–230 V AC, 50–60 Hz • Maximum power consumption: 300 VA Condition: • Used. • Visual condition as shown in the photos – normal signs of use.

Condition: excellent (used), I am offering for sale a Tektronix DPO 4032 Digital Phosphor Oscilloscope. The device is fully functional, starts up without any issues, and operates correctly. It displays the startup screen and the measurement screen, as shown in the attached photos. The cosmetic condition is good – it has normal signs of use resulting from operation. Technical specifications: Pgjdpfxjzru Hme Aphjr • Manufacturer: Tektronix • Model: DPO 4032 • Type: Digital Phosphor Oscilloscope • Bandwidth: 350 MHz • Sampling rate: up to 2.5 GS/s • 2 analog channels • Color LCD display • Interfaces: LAN, USB Host, USB Device, VGA, CompactFlash • Power supply: 100–240 V AC, 50–60 Hz Condition: • Fully functional. • The device starts up and operates correctly. • Sold without measurement probes and other accessories. • The set includes only the oscilloscope shown in the photos.