... DIN JIS copper sleeve Specifications:1) Suitable for various automotive, electronic, telecommunications, mechanical products, medical devices, etc ... grinders, instrument lathes and accessories like drills, mill devices, Mitutoyo concentric circles, optical projectors, Mitutoyo fineness ... optional can be as requirements6)Material: iron/aluminum, copper, alloy, carbon steel, 18CrMnTi,20CrMnTi,20Cr,20CrV, ...