... twist wire1.Ideaful to clean rust, paints, welding burs in heavy duty ,High efficiency, long working life ,Reliable quality, good material2 ... ,black,zinc plated etc3.wire material:twist knot wire cup brush with thread type of wire:knot steel wireS:steel wire 0.35,0 ... .5mmSS:stainless steel wire:0.35,0.4,0 ...