A Booster adds additional axle spread for legal hauling during restrictions and added weight capabilities during permit loads. The Booster Axle Assembly may use Mechanical, Air or Hydraulics to provide load transfer. Trail King offers models that have Shims to allow for adjusting the amount of load the axle transfers. These options can come with fixed axles, Pin-on, or a flip axle and can be combined or used individually with trailer for even more versatility. Most commonly, Boosters are used in heavy hauling situations where weight regulations and specific axle loads are critical. Trail King offers several Booster options.