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 440C 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.