QA1's WPB - T and WPB - TG Wide Stainless Steel Series spherical bearings are a precision grade spherical bearing. Each bearing is made from Stainless Steel with a PTFE liner and has tighter tolerances than traditional spherical bearings. Also available with this series is an optional staking groove (WPB - TG Series). 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 heat treated stainless steel.