Bronson Speed Co. Next Generation Ceramic Bearings designed for today's skateboarding. Bearing Cleaning Unit Package - Case doubles as a bearing cleaning unit by following the included instruction sheet. 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. Deep Groove Raceways - Balls roll deep in raceway channels - reduces side impact damage & breakage. Straight Edge Frictionless Shields - Pop off resistant - hold oil in, dirt and moisture out - easy to clean.Max Impact Cage Design - non- distortion custom cage keeps the balls precision spaced & oil circulating.Micro Groove Raceway Surfaces - linear micro-groove surfaces improve bearing lubrication, speed and spin.High Speed Oil - Custom engineered light oil lubricant is water, oxidation and corrosion resistant for extended wear protectionBalls Out Technology - Eliminates shield and cage contact on impact for a go fast, stay fast bearing.Factory Fresh Quality - Nitrogen filled shrink wrap, reduces metal & oil oxidation until ready to be ridden.Package inludes: Bearing cleaning unit case, 8 ceramic bearings, 4 spacers, 8 washers, and 8 extra replacement shields