Specification AutoPartPosition : inner Brand : ACROPIX BulletPoint1 : 2 Pcs Universal Bearing Steel Linear Ball Bearings. BulletPoint2 : Feature: These LMK12UU Linear Ball Bearings are made from durable bearing steel, size: 12x21x30mm. BulletPoint3 : To replace your Linear Ball Bearing if it made noise, cracked, low speed and bad friction while working. BulletPoint4 : Easy Installation - The table needs to be level during installation, otherwise it will interfere with installation calibration. BulletPoint5 : Note: Please confirm the model number and dimension before buying, thanks! Color : Silver Tone ExteriorFinish : Aluminum ExternallyAssignedProductIdentifier : 8070716396119 FinishType : Silver FitType : Universal IncludedComponents : block ItemName : ACROPIX LMK12UU 12mm IDx21mm ODx30mm Length Square Flange Linear Ball Bearings Silver Tone - Pack of 2 ItemPackageDimensions_Height : 9.7 centimeters ItemPackageDimensions_Length : 5.1 centimeters ItemPackageDimensions_Width : 7.8 centimeters ItemPackageQuantity : 2 ItemTypeKeyword : linear-ball-bearings Manufacturer : ACROPIX Material : Bearing Steel Material1 : Metal Material2 : Rubber MeasurementSystem : Metric MetalType : Aluminum ModelNumber : accar2305200012 NumberOfBoxes : 1 NumberOfItems : 1 PartNumber : accar2305200012 ProductDescription : Features: Pre-lubricated, smooth and flat bearing surface, compact structure, with strong bearing capacity and dust-proof, long service time. Suitable for high-speed, low friction, low-noise and low vibration, improve efficient and steady work. High temperature quenching forging, sturdy and durable in operation, these deep groove ball bearings combine radial and load at high speed. Mainly applicated with guideways of linear tables, 3D printers rail unit, engraving machines and other common machine guideway etc.