Acting like a cap for your wheel bearings. CURT bearing protectors provide a reservoir of grease to lubricate your wheels and keep them turning smoothly mile after mile, plus they cover the bearings so that mud, rain, road grime and more are kept out. Maintains pressure & keeps bearing greased Features a small reservoir to keep bearings well-lubricated Includes two protectors & two dust covers | Curt Bearing Protectors, Set of 2 with dust covers, 1.78" hub Diam