Features [Shaft Fixation] These shaft collars are used for linear rail shaft fixation and positioning, ideal for DIY CNC machine tools. Featuring 12mm inner diameter, 30mm outer diameter, 10mm thickness. [Seamless Integration] Designed to perfectly mesh with the shaft, this linear rail stop collar ensures easy installation and a tight fit, enhancing stability. [Secure Fastening] Equipped with a M4 fixing screw, the limit fixing ring securely clamps onto the shaft without causing damage, providing reliable and stable fixation. [Aluminum Alloy Made] Crafted from aluminum alloy, this shaft stop collar is lightweight yet sturdy, not easy to be broken or damaged. [Corrosion Prevention] Its surface is resistant to oxidation and corrosion, ensuring long lasting performance even in demanding environments. Specification: Item Type: Linear Rail Shaft Collar Material: Aluminum Alloy Inner Diameter: Approx. 12mm/0.47in Outer Diameter: Approx. 30mm/1.18in Thickness: Approx. 10mm/0.39in Screw Hole: M4 Package List:4 x Linear Rail Shaft Collar Package List 4 x Linear Rail Shaft Collar