PRODUCT SPECIFICATIONSPart #: 0000-120695Fastener Type: Square Head Machine BoltSize Description: 1/2"-13 x 1 3/4"Diameter/Nominal Size: 1/2"Length: 1 3/4"Wrench Size/Across Flats: 0.725-0.750"Width Across Corners: 0.995-1.061"Head Height: 0.308-0.348"Thread Pitch: 13Thread Direction: RightSystem of Measurement: InchGrade: A (2)Material: Low Carbon SteelFinish: Hot Dip GalvanizedHead Type: SquareDrive Type: External SquareStandards Met: A307Average Piece Weight: 0.1183000 lbs.Square head bolts, or square head machine bolts offer a large bearing area for positive gripping; primarily used nowadays for aesthetic projects that create a rustic look or to match existing fasteners; comes in both fully threaded and partially threaded pitches. Square head bolts are sometimes selected over hex heads because the head will fit neatly in a channel.