The M5 x 25W10 JIS B1188 Phil Pan Split Washer Flat Washer Sems M/S Zinc is a type of fastener used to secure two or more pieces of material together. It is made of zinc-plated steel and has a split washer and a flat washer attached to it. The split washer helps to distribute the load of the fastener and prevent it from loosening, while the flat washer helps to protect the surface of the material being fastened. The fastener is designed to be used with M5 screws and has a length of 25 mm.