A linear ball bearing (also called ball bushing or shaft guiding) consists of a polymeric cage with raceway segments made of hardened steel to guide the ball sets within the complete system. The recirculating balls provide unlimited stroke and low friction movement. You can power linear ball bearings by either a drive mechanism, inertia or by hand. Steel snap-rings fit perfectly in the lip of these bearings. These bearings are great for applications such as 3D printers, animatronics, and other projects requiring a low friction slide mechanism.