... technology production Material Option:1.Bearing Material:carbon steel,chrome,stainless steel,iron,copper,ect.2.Roller Material:POM, ... 62,69,68,6000series, and non-standard bearing series,toy bearing series and sport equipment series.Roller:all ... produce miniature deep groove ball bearing or carbon steel, bearing steel, stainless steel, non-standard bearing and injection molding roller and dysmorphism ...