The Helo Quark Bearings were built for players looking for the fastest roll that money can buy in the roller hockey market. The Quark Bearing utilizes a glass-reinforced nylon cage, deeper raceways and premium elite-performance speed lubricant that leaves even Helo's own Swiss bearings in the dust. To make cleaning the bearings super quick and thus extending their life expectancy, the backsides are easily removable so you can clean and re-lube them on the fly. Included 16 Helo Quark Bearings. Standra 608 with 8mm bore. Serviceable.