Core made of High-Carbon AISI 52100 Chromium Alloy Steel features higher wear resistance, fatigue strength and steel hardness, Premium quality MolyPro™ NLGI Grade 2 Molybdenum Grease (MoS2) to minimize wear and reduce friction providing longer lasting performance, Exclusive multi-lip seals are made with ProSeal™ Nitrile Rubber (NBR) which can successfully function at high delta of temperatures while retaining its flexibility and sealing performance, Inner rings are made of Case-Hardened Steel for improved resistance to surface wear and contact fatigue, Thickness and metallurgy electronically validated for manufacturing consistency, SAE J1714, J2525 and J2535 validated for OEM load-carrying capacity, durability, and performance characteristics, Part Reference Numbers : 1410-634899 91-634899 94-634899 S510122 NT510122 WH510122 510122 WB000104 TRB-510122, Part Reference Numbers : WE61910 S511047 NT511047 WH511047 511047 GRW28 WB000103 TRB-511047, Kit Includes: 2x Front Wheel Bearing (Both Side) + 2x Rear Wheel Bearing (Both Side)