For a precision spherical bearing, QA1's NPB-T Narrow Stainless Steel Series spherical bearings are the perfect selection. Each bearing is made from stainless steel with a PTFE liner and has tighter tolerances than traditional spherical bearings. The ball is made from 440 C stainless steel that has been heat treated, hard chrome plated and precision ground. The PTFE liner is self-lubricating, and the race is made from heat treated stainless steel.