... bearing Size: 7*17*5mm Bearing material: carbon steelProduct Feature:1.Low coefficient of product,reduce tire damage 2.Running ... the adoption of advanced technology production Material Option:1.Bearing Material:carbon steel,chrome,stainless steel,iron,copper,ect.2 ... industry, which is mainly produce miniature deep groove ball bearing or carbon steel, bearing steel, stainless steel, non-standard ...