WIDE APPLICATION: SBR12 shaft collars mainly used for shaft fixing and positioning, linear guide stop for DIY CNC machine tools. Widely used in electronic equipment, food processing, mechanical equipment, textile printing, it is a high quality choice for precision instruments and industry. STRONG AND STURDY: Our SBR12 linear guide stop collars are made of high-quality aluminum alloy with high hardness and anti-. The is naturally anodized for durability. The screws are made of high-quality carbon steel and are rust-. EASY TO USE: Designed to engage fully with the shaft. Slide the ring onto the shaft and use a wrench to tighten the screws to hold the ring in place without any complicated procedures. Colour:Silver Material:Aluminum Alloy Package Contents: 4 x Linear Rail Stop Collars 1 x Wrench Only the above package content, other products are not included. Note: Light reflection 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.