These shackles take the place of S-hooks and need the wrench, H175, to open and close. This head makes removal, because of vandalism, more difficult. These are used when a wide opening is needed. The overall length is 3 9/16”. The bolts are 3/8” in diameter. The inside of the smaller opening is ½” across and the larger opening is 1 3/16”. Unlike S-hooks they can be used multiple times. They are also much easier to install then S-hooks and much stronger. Tensile strength 9491 lbs.