Hex cap screws are bolts with hexagonal heads and machine threads for use with a nut or in a tapped hole. These screws are bolts with a washer face under the head. Use these grade 5 partially threaded screws anywhere a hex bolt may be used. Tighten with a wrench or a drill. * USS grade 5 partially threaded along the shankScrews feature a washer face under the head for a better sealHeat-treated zinc finish for extra strength and wear resistance