Kit Details: 4 SBR20 Linear Guide Limiters; Our linear stop bushings securely fix your shaft and position it precisely. With an inner diameter of 20 mm and an outer diameter of 40 mm, they are perfectly suited to your needs. Stable Holding Force: Our unique set screw design ensures increased holding force, especially if the shaft material is softer than the set screw material. You can rely on reliable and secure fastening. HIGH QUALITY MATERIAL: This linear guide limiter is made of aluminum alloy. It is corrosion-resistant, high-strength, and wear-resistant. In addition, it is easy to install and maintenance-free. EASY INSTALLATION: The clip-on wave rings are designed for quick installation in large openings. They are securely fastened and do not come off easily. The shaft is clamped firmly without being damaged. APPLICATION: Suitable for installation on various machines, such as: engraver, woodworking machine, printing machine, DIY CNC milling machine, 3D printer.