ARC developed these brackets for use with our large ladder bars (over 33" long). They greatly simplify moving the front mount of the ladder bar, without the need to then try and re-align the pinion angle. With these brackets, you simply remove all the bolts and lower or raise the ladder bar to achieve the desired result. Customers tell us that it is much quicker and easier than the conventional method which often creates enormous bind in the adjusters while trying to re-align the pinion. Bolt hole spacing is 22mm with the middle hole of the 3 being the same as our standard bracket.