That's Mac who uses the tubing frame. This is all wood. This is all full-dimension lumber I get from a mill. Mostly 2x6s and 2x8s. On the back I use a 2x6 with a 6x10 on top of that to lift the box then set it down 4x4 and 4x6 in back and a 4x4 toward the front of the box.windmill said:Is the 2" tubing inside the wooden form I see there? Would the 2" posts be the same type as is used in some basement house supports? I like the versatility you have being able to back the truck in and not loose any space.