Some times a good set of leaf springs can be just a little too flexible and cause leaf spring inversion, this is when the shackle tries to flip upside down and the eye of the leaf spring hits directly on the frame, Boomerang Shackles are an ideal way to prevent this.  We offer our Boomerang Shackles in three different lengths of 4", 5", and 6" between the center of the bolt holes.  The shackles are cut from 1/4"steel and have 1/2" bolt holes.  These shackles are sold individually, you will need two of these to make one complete shackle.