All the mating surfaces of this expansion box are machined flat for a tight seal. The die retainer ring and the hardware is made of steel. All outside surfaces are powder-coated for a durable lasting finish.
The kit includes: the expansion box, die retainer ring and mounting bolts, hex wrench, three-piece spacer board and lag bolts.
All dies are made of machined 3/4 inch HDPE polyethylene. In general, the walls of extrusions are 3-1/2 inches or less and 1/4 inch thick, while larger pieces have 5/16 inch walls. All dies are also counter-sinking around the edges or where the brace passes through the extrusion. This is to add in healing of hollow shapes and give even pressure around the opening.