Bearing Buddy Protector with Bra - 1.98"Why is a Bearing Buddy; needed?Boat trailer hubs get warm while traveling to the ramp.  Warm hubs backed into cool water during launching are suddenly cooled which contracts any air inside the hub creating a vacuum. The vacuum pulls water and road grit inside the hub contaminating the grease.  The contamination causes corrosion and rapid wear. Perfectly good bearings can be ruined in less than one season.Bearing Buddy; corrects this problem by filling the entire hub with grease. Most air that is trapped inside the hub will be expelled by the Bearing Buddy; pressure relief feature. Once the hub is full, the spring loaded piston in the Bearing Buddy; exerts a slight pressure to the grease inside the hub.  With the pressure inside the hub slightly higher than the pressure outside the hub, water and grit cannot be drawn inside. An automatic pressure relief feature prevents over-filling the hub which would damage seals.Features:Fits hubs with an inner diameter of 1.98"50.41mm hub boreOuter bearing cone: L-44643, L-44649, L-44640Outer bearing cup (race): L-44610Stainless SteelBlue indicator ring to easily view if there's positive pressure in the hubSold in pairs