Bearing Cleaning Unit Package - Case doubles as a bearing cleaning unit by following the included instruction sheet. Package inludes: Bearing cleaning unit case, 8 ceramic bearings, 4 spacers, 8 washers, and 8 extra replacement shields. Factory Fresh Quality - Nitrogen filled shrink wrap, reduces metal & oil oxidation until ready to be ridden. High Density Ceramic Balls - Precision made, Hot Isostatic Pressure Sintered (HIPS) Silicon Nitride ceramic balls are super-fast, smooth rolling, and durable for extended use. Balls Out Technology - Eliminates shield and cage contact on impact for a go fast, stay fast bearing. High Speed Ceramic Oil - Nano-ceramic compound for wear protection - moisture, rust, & corrosion resistant. Micro Groove Raceway Surfaces - linear micro-groove surfaces improve bearing lubrication, speed and spin. Max Impact Cage Design - non- distortion custom cage keeps the balls precision spaced & oil circulating. Straight Edge Frictionless Shields - Pop off resistant - hold oil in, dirt and moisture out - easy to clean. Deep Groove Raceways - Balls roll deep in raceway channels - reduces side impact damage & breakage.