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, Bearing already mounted and secured on the assembly to required OE torque specification for easier and faster installation, Part Reference Numbers : 1411-44545 WE60519 SEE 91-09871 SEE 94-09871 S512183 NT512183 WH512183 663183 H512183 512183 GRW241 TRB-512183, Kit Includes: 2x Rear Wheel Bearing Assembly (Both Side)