QA1s COM Series is the perfect traditional spherical bearing choice. Each bearing is made from chromoly steel with an option for Teflon self-lubricating PTFE liner. BALL ·52100 Bearing Steel ·Heat Treated ·Hard Chrome Plated ·Precision Ground LINER (Teflon only) ·PTFE ·Self-Lubricating RACE ·Chromoly Steel ·Heat Treated ·Protective Coated for Corrosion Resistance