High-speed ball-bearings manufactured especially for XRAY with low radial play. ID x OD x thickness (mm) = 6x10x3. Set of 2 pieces. Top-quality expert ball-bearings for a super-free, super-smooth drivetrain. These highest quality ball-bearings are fitted with special rubber covers, and therefore are degreased and lightly oiled with AeroShell Fluid 12 oil for optimum smoothness, longevity, highest threshold and optimum performance. These ball-bearings do have more (and larger) balls inside the cage compared to the regular ball-bearings, making them even more resilient under lots. Along side it covers are really easy to remove for fast and comfortable servicing. These ultra-high accuracy ball bearings are designed to withstand all extremes on track under racing conditions and/or just fun racing.