Core made of High-Carbon AISI 52100 Chromium Alloy Steel features higher wear resistance, fatigue strength and steel hardness, mPulse unique technology ensures the electronic control systems track physical or substance changes and turn them into electrical indicators with unmatched precision, Premium quality MolyPro™ NLGI Grade 2 Molybdenum Grease (MoS2) to minimize wear and reduce friction providing longer lasting performance, Engineered with high-quality material to ensure long-term performance and the capability to resist high temperatures, 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, Made with corrosion-free coating for highest durability on the market, Inner rings are made of Case-Hardened Steel for improved resistance to surface wear and contact fatigue, Kit Includes: 2x Rear Wheel Bearing (Both Side) + 2x Rear ABS Wheel Speed Sensor (Both Side), Kit Variations: K7S-100330 K7S-100666