The M4-0.7 x 45W9 JIS B1188 Phil Pan 304SS Split Washer 302/304SS Flat Washer Sems A2 Stainless is a high-quality washer set designed for use in a variety of applications. The split washer is made from 304 stainless steel and is designed to prevent nuts and bolts from loosening due to vibration or movement. The flat washer is also made from 304 stainless steel and is used to distribute the load of a nut or bolt over a larger surface area. The set is completed with a Sems screw, which is a screw that has a washer pre-assembled onto it. This make