These patented Ultra-Tow High-Performance Stainless Steel Trailer Bearing Protectors protect hub bearings on all types of trailers from water and dirt. Kit includes two bearing protectors featuring grease level indicators, which indicate when grease should be added. Bearing protector covers sold separately. Included (qty.): 2, Material: Stainless steel Patented grease level indicatorProtects bearings from dirt and waterStainless steel constructionBearing protector covers have retaining bands to keep covers from falling off protector during towing. (sold separately)