The Brophy model PHBP Mounting Bolt Pack is made for use with Pintle Hooks and includes 4 sets of Bolts, Nuts, and Washers. The length of each bolt is 2-1/4", of which 1-1/4" is threaded, 1/2" is smooth, and the remaining 1/4" makes up the bolt head. The diameter of the threaded part of the bolt is approximately 1/2" in diameter.