... steel 2.specification: A/M/UM/KM 3.standard: DIN6499 ER NUTS (DIN6499 D & E )1.material:spring steel2.specification: A ... :We are a manufacturer established in 2003. Specialized in design, manufacture and marketing of machine tool accessories.Production includes ... collet series,boring heads series,tapping chuck series,pull studs,er nuts,centers,mores taper sleeves,drill chucks,precision tool vises, ...