4-40X516 Phillips Pan Split Lock & Narrow Flat Washer Sems Fully Threaded Zinc (Pack Qty 10,000) BC-0405SNPP

A pan head machine screw with a free-spinning lock washer and flat washer manufactured as one assembly The washer/screw assembly makes this a locking screw with the helical washer providing the locking action and flat washer distributing the load over a wider area