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 : 1410-41243 WE60639 91-41243 94-41243 S513130 NT513130 WH513130 H513130 513130 GRW219 GRW200 TRB-513130, Part Reference Numbers : 1410-255695 WE60836 91-255695 94-255695 S510083 NT510083 WH510083 H510083 510083 FW187 TRB-510083, Kit Includes: 2x Front Wheel Bearing (Both Side) + 2x Rear Wheel Bearing (Both Side)