[SIZE] - M3 x 0.5mm. [MATERIAL] - Made of carbon steel, surface is zinc-plated for good rust resistance.. [ADVANTAGE] - It is used in places where frequent adjustment or disassembly of fastener connections is required. No tools are required to install the product, just turn your hand to complete. [APPLICATION] - Machinery and equipment, electronic equipment, communications equipment, hardware lighting, building bridges, furniture decoration, etc. [PACKAGE CONTENT] - 15 x Wing Nuts.