This 4-Piece, Bolted Frame is made of 1.5" x 3" electroplated steel tubing (which helps reduce rust).  The modular frame is bolted together, eliminating busted welds.  When this main frame "accidentally" runs into something, you just replace parts, not the whole unit.

The triangular shaped Gusset and individual arms (front, left, right) can be purchased separately, please call 800-571-6143 to order and specify which arm is needed.