M3 x 12W6 JIS B1188 Phil Pan Split Washer Flat Washer Sems M/S Zinc Yellow are a type of washer that is used to distribute the load of a screw or bolt over a larger surface area. They are typically used in conjunction with a flat washer and are designed to prevent the screw or bolt from loosening due to vibration or movement. These washers are made from steel and have a zinc yellow finish for corrosion resistance. They are available in a variety of sizes to accommodate different screw and bolt sizes.