The 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. Recirculating balls provide unlimited stroke at low friction movement. 
 

Linear ball bearings are also available in a range of units that feature lightweight, cast aluminum housings. Combined with shafts and accessories, this complete offer can be used to develop simple, cost-effective linear guiding systems for a wide variety of application

Linear Bearings