The KRYTAC 8mm Caged Ball Bearing Bushings support the gears to stabilize rotation and reduce friction and heat. Not all bearings are created equal, though they look the same, the difference between one set of bearings to another is in the build materials and quality of construction. KRYTAC 8mm Caged Ball Bearings are precision machined from Japanese steel and carefully assembled for optimum performance that lasts. The inner and outer raceways are specifically measured as a perfect fit for the caged bearing group to evenly distribute the load on the bearing and reduce friction and heat. KRYTAC 8mm Caged Ball Bearing Bushings allow gears to spin smoothly with as little resistance as physically possible.