Applicable within the countersunk hex bolt mechanical fastening assembly furniture fixed connectors, screws countersunk head screws Phillips has the word countersunk head screws countersunk head screws binaural single inner ear cup head bolts hex head bolts hex bolt grade level has 4.8 8.8 10.9 12.9 Material variety of model specifications complete a variety of custom-shaped head of the large thick hex head bolts unlimited number of quality assurance