these are made for the DIY with a mig welder who wants to do his own system, but doesn't want to suffer making these things because the are a pain. the runners are 2.00" and are about 4" long. they can be butt welded or stretched to slip fit up to 2.25" tube or butt weld up to 2.50" tube. just select the one you want from the drop down menu. thanks for supporting Monkey Fab!