SEMS screw  is a screw with one or more washers. The screw part has a wide range of size, which could be as small as M1.0. The washer could be flat waher, split spring washer, wave washer, external or internal tooth washer, or other special washers. Carbon steel, stainless steel, brass, aluminum, plastics, etc could all be used. Surface treatment could be chosen among nickel plating, zinc plating, chrome plating, oxidization, anodization, etc. Painting on the surface is available as well.