... steel 2.specification: A/M/UM/KM 3.standard: DIN6499 ER NUTS (DIN6499 D & E )1.material:spring steel2.specification: A/M ... tool accessories.Production includes milling chuck series,CNC tool series,collet series,boring heads series,tapping chuck series,pull studs,er nuts,centers,mores ... taper sleeves,drill chucks,precision tool vises,parallel block series,V-block clamp,etc.Sales covering the USA,Germany ...