Precision grade ABEC-1, maximum speed 34000, with grease. Pre-grease, low friction, no maintenance Single row radial ball bearings for applications supporting radial and axial loads Easy to disassemble and reinstall. Perfect products for medium loads: skateboards, inline skates, scooters, inline blade electric motors, bicycles, motorcycles, electric hand tools, etc. In many other scrolling applications In many other rolling applications, refitting a worn skateboard to an inline blade electric motor of a skateboard scooter, wheels of bicycles and motorcycles, automobiles, electric hand tools, etc. Please check the size / dimensions or accuracy class (if suitable for your equipment). For ball bearings, the radial internal clearance is C3, so that the radial slack between the inner ring and the outer ring is CN (normal) to compensate for thermal expansion. Heat treatment is performed to increase hardness to improve wear resistance. It has deep ball grooves in both seat rings and can