This item is made from quality 304 stainless steel and is a very handy fastener to connect torque arm brackets and other components to side frames. The external hex portion acts as a natural spacer. The hex portion is 1/2″ hex. The Hex is tapped M8-1.25X21 female. The male is M8-1.25X18. It is very versatile and a handy part for your inventory.