Replace the standard dust caps in the center of your trailer's wheels with wheel bearing protectors by Bearing Buddy. Made of stainless steel that's an especially good choice for use in and around salt water, they provide exceptional protection from road debris, dust, water, and other things that might contaminate the lubricated bearings, causing excessive wear. Your bearings are further protected by Bearing Buddy's ability to add lubrication to the bearing without the need to remove the cap at all. And don't worry about knowing when to add more lubricant. When you order these wheel bearing protectors from SkipperMate Marine, you'll also receive a blue ring which acts as a visual indicator of the amount of lubricant inside the hub. For ease of ordering, these bearing protectors are sold in pairs. We make a point of staying well stocked enough to ensure minimal wait times on all of the orders we receive.