Item: Radial Ball Bearing, Bearing Type: Double Shield, Bore Dia.: 20mm, Bore Tolerance: +0/-0.01mm, Outside Dia.: 52mm, Outside Dia. Tolerance: +0/-0.013mm, Width: 15mm, ABEC Tolerance: 1, Dynamic Load Capacity: 3,580 lb., Static Load Capacity: 1,780 lb., Max. RPM: 17,000, Temp. Range-40 Degrees to 350 Degrees F., Bearing Material: 52100 Chrome Steel, Cage Material: Pressed Steel, Shield Material: Pressed Steel, Lubrication: Polyrex EM Grease,  Industry Number: 6304-ZZ C3.