Bolun is able to offer a wide range of ball bearings by adjusting different material to both the "body" of support and the ball bearings themselves. Materials of the support body: Aluminium Alloy 6060 (P-AlMg0.5Si0.4Fe UNI 9006/1 "ANTICORODAL") Steel Alloy FePO4 - Zamak ® Nylon® Materials: 1.Metallic parts of the ball bearing can be made in: 11SMnPb37 Carbon Steel Stainless Steel AISI 303 /304 / 420 / 440 100Cr6 (AISI 52100) Chrome Steel Bronze Alloy G-CuAl1 14Fe4Ni UNI 5275 2.Plastic Coatings or Metallic Ring Edge: Type 6 Polyamide (Nylon 6 ®) - Type 6.6 Polyamide (Nylon 6.6 ®) - Acetal Resin (Delrin 100/500/900 ®) - Rubbers (Vulkollan ®) Furthermore, on request, we can add to the plastic compound other raw elements such as FIBER GLASS or the MOLYBDENUM BISULPHIDE (MoS2) to improve the plastic mechanical characteristics (i.e. shove resistance/duration/loading capacity) or to better bearing sliding. For more information,please feel free to contact with us.