The base is made from square tubes that are 2 by 2 by 1/4 inch. Round 1 1/4 by .20 DOM tubing makes up the sides along with a raised loop to better protect the quarter panel and bed. These sliders are attached by 3 legs made of the same square tubing as the base. These 3 legs are welded to diamond shaped plates which are about 3/16ths of an inch. Installation does require welding.