Bones Swiss Ceramics are in a class by themselves. If you want the best there is, this is it. The Cerbec® Ceramic balls are much lighter, harder, stronger, and longer lasting than the finest steel balls. Features Accelerate faster Roll faster and farther Resist dirt and moisture better Help to repair injuries to your races caused by dirt High speed Nylon® ball retainer for greater strength and speed Skate Rated™ clearances, tolerances, materials and lubricant provide the best performance and durability possible. Sticker Contents Set of 8 bearings 4 bearing spacers Instructions Sticker Please note you need two packs for skates