I have a length of yellow electrical tape hanging down from the forward face of the lower front right corner of the camper tub. When I back the truck under the camper for loading, the yellow tape drags along the truck bed about 2 inches inside from the wheel well. I can see it while backing the truck under the camper and know where it should be dragging during the loading process. As long as the tape is moving along that known line in the truck bed, I know the camper is lined up and usually loads first time without fail.