Industrial-grade standard SBR block, with high 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 rail positioning. Perfect for your DIY routers, mills, lathes. Aluminum alloy support rail with pre-drilled holes for ease of mounting. Type: Linear Glide path: linear Rated dynamic load: 860 Rate static load: 1370 grade: H Fixed size: 8 (mm) Fixed mode of sliding block: Locking type Allowed static torque: 1 (kn.m) Weight:1050g colour:Silver Material:metal size: Linear Rails- 500mm / 19.7inch (Length) x 12mm / 0.47inch (Diameter); Linear Bearing Side Blocks -40mm x 40mm x 28mm/1.57 x1.57 x1.10inch( Length x Width x Height) Package Contents: 1 x linear 2 x Linear bearing slider Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.