5/16-18 x 2" 12 Point Flange Screw - 170M PSI - Steel - Plain - Partial Thread - UNC - Pkg of 25 - B2176384

TWELVE-POINT DRIVE TYPES HAVE A COMPACT HEAD SHAPED INTO TWELVE TRIANGULAR POINTS. THEY DISTRIBUTE TORQUE WELL AND ARE USED WITH TWELVE-POINT WRENCHES AND SOCKETS.