I use 2 1/2 x 2 1/2 x 3/16 wall. It is slight slop to it but it is cheeper. I get it by the 24 ft stalk. They will not obviously have that outer lip that a true receiver has, but that doesn't bother me. I have built bumpers and without that lip I was able to make it flush in the face of the bumper. Has a nice look to them. Just my 2 cents