6207: inner diameter 35mm outer diameter 72mm width 17mm Advantages of a quality bearing in place: optimized material, ingenuity, quality stability, higher speed, lower noise, longer life. Material: gb grade bearing steel. Bearing steel is preferred, bearing steel has stronger performance than ordinary material. Sealing type: ZZ/RS/ open Radial clearance: CO/C2/C3 can be customized Hardness H: 60-63/50-55 Cage type: wave cage/nylon cage/crown cage Vibration/noise level: Z1-Z4