This easy to use conversion kit eliminates your trucks old ball bearing type wheel bearings with modern tapered roller bearings. Old style ball bearings can fail due to modern driving and road conditions making your truck unsafe. Tapered bearings can handle more side load and can deal with modern roads. Things like radial tires and rain grooves and disc brake upgrades that would cause ball bearing to fail will have no effect on tapered roller bearings. Sold in pairs with (2) inner bearings, (2) outer bearings and (2) grease seals.