Trailer Leaf Spring Shackle Bolts 9/16" -18 X 3" long with Lock Nuts, Set of 4 -23030/23012 9/16"-18 x 3" trailer leaf spring shackle bolts and locknuts for mounting slipper spring onto hanger bracket or equalizer, Diameter: 9/16";Threads per inch: 18;Length: 3",Grade: 5 9/16-18 lock nuts Mostly used on mounting 1-3/4" wide leaf springs onto hanger brackets or equalizers 4 bolts and 4 nuts