1/4 -20 x 1-1/2 Zinc Grade 2 / A307 Square Head Bolts (12 pcs.)

Diameter: 1/4 Length: 1-1/2 Material: Steel Finish: Zinc Head Style: Square (3/8 Wrench) Thread Size: 20 (Coarse) Hardness: Grade 2 / A307 Type: Square Head Bolt Box of 12. A square head bolt has a four-sided head. Compared to standard hex bolts square bolts have a greater surface in contact with the part being fastened and therefore provide greater resistance to loosening (though also greater resistance to tightening). Square bolts are typically mated with square-headed nuts.