... , C2, C3, C4, C5 5) Material: AISI52100, AISI440C, AISI304, AISI316, Ceramic 6) Retainer: PTFE, Nylon, PEEK or Stainless ... , C57. Bearing material: bearing steel (9Cr18), stainless steel(AISI440C, AISI304, AISI316), ceramics8. Keeper: stainless steel, PTFE, nylon9. Bearing ferrule ... , C2, C3, C4, C5 5) Material: AISI52100, AISI440C, AISI304, AISI316, Ceramic 6) Retainer: PTFE, Nylon, PEEK or Stainless ...