Features: 84mm wheels are designed for reliable performance at a greater value 84mm/SG7 bearings/6mm spacers 84mm/84A wheels are higher upgrade value replacement wheels Easy replacement SG7 Bearings and Spacers SG7 silicone/grease helps limit friction and increase speed Wheel kit includes: (8) 84mm wheels, (16) SG7 bearings, and (8) 8 mm spacers preassembled for replacing wheels