THIS MIL-RITE OR MIL-MASTER BLACK" course Thread", we will send aluminum knob instead of plastic of plastic knob is not available in plastic, ADJUSTMENT KNOB COMES WITH THREE WASHERS. THIS KNOB IS FOR BOTH THE MIL-RITE AND THE MIL-MASTER MILLS FOR ADJUSTING THE FLOUR TEXTURE SETTING ON THE GRINDERS. PLEASE BEFORE ORDERING CHECK THREADS ON KNOB.