Kugel Bearings use premium quality Chevron Grade 2 molybdenum grease, Exclusive multi-lip seals are made with Nitrile Rubber (NBR) which can successfully function at temperatures of-40°C while resisting contaminants from fluids and debris, Manufactured with CNC tooling, automated grinding and assembly lines for increased consistency, Inner rings are made of AISI 52100 alloy (high carbon) steel, low-alloy chromium steel, which meets ASTM International quality standards, Core made of high tensile, heat-treatable AISI 1065 high-carbon steel, Assembly is precision processed and pre-coated with anti-corrosion lubricant, it not only makes lubricating the bearings easy, but also helps prevent corrosion of the hub, Part Reference Numbers : BR930900 KH4510, Kit Includes: 2x Rear Wheel Bearing and Hub Assembly (Both Side), Part Reference Numbers : BR930900 KH4510