Industrial-grade standard SBR block, with high precision linear bearing inside.Surface silver plating treatment, beautiful anti-rust, hardness can as high as HRC62, more durable.The adjusting handle can adjust the tightness of the slider.Standardized processing, perfect for guide rail positioning. Perfect for your DIY CNC routers, mills, lathes.Aluminum alloy support rail with pre-drilled holes for ease of mounting.Type: Linear slide guideGlide path: linear guideRated dynamic load: 860Rate static load: 1370Precision grade: HFixed bolt size: 8 (mm)Fixed mode of sliding block: Locking typeAllowed static torque: 1 (kn.m)Weight:2100gcolour:SilverMaterial:metalsize: Linear Slide Rails- 500mm or 19.7inch (Length) x 12mm or 0.47inch (Diameter) Linear Bearing Side Blocks -40mm x 40mm x 28mm or 1.57 x1.57 x1.10inch( Length x Width x Height)Package Contents:2 x linear guide4 x Linear bearing sliderOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.