High Precise ER Type Spanner(Wrench) 1.Material:65Mn 1.ER8, ER11, ... 50 2.A,M,UM and K type ER spring collet spanner1.Type:ER 8, ER 11, ER 16, ... up to ER 50 2.Model:A type, M type, UM type and K type.3.Material:65Mn steel Package:Company ... specialize in design, manufacture and marketing of machine tool accessories.Production includes milling chuck series,CNC tool series,collet series,boring heads series, ...