The heavy duty kit includes 1/2” shackle brackets, bronze bushings, greaseable or “wet bolts” and nuts. The 1/2” shackle links are a stronger, more durable product that is much less subject to having the bracket elongate. The bronze bushings and wet bolts provide an opportunity for periodic lubrication that will greatly extend the product life. The heavy duty shackle kit is available for both tandem and triple axle trailers and will fit units with upgraded suspension systems. Thicker shackles for added strength Bronze bushings for more durability Greasable bolts for less maintenance Fits Stock or Equaflex with 3-1/8" shackles Tandem Axle MODEL NO - UO12-021