Rear Bumper Endcaps / waste pipe storage

This is a more secure replacement for the end caps that keep the poop hose in the rear bumper on a camper. These fit a nominal 4" square pumper as found on a Forest River camper. There is a guide to correctly center the hole to be drilled in the bumper. The press-in covers provided kept trying to jump out as I was driving. A 4.5" 1/4x20 screw and wing nut is needed for each end.