My '88 Chevy C-30 Bonus Cab 8 FT Bed Dually is 21 feet long and this cover fits perfectly. It hides well under the bumpers and down to the bottom nut (truck lowered 5"F/4"R). The only "problem" is that the side mirror pockets are about 8 inches farther from the real mirrors, so I put them in myself (4th pic). Since the mirrors fold, it doesn't bother me. I put it on a month ago full of snowstorms with combined winds of 25+ inches and 35+ mph in all directions. I only used the waist belt that came with it and it never moved. As a side note, I put 4 bins on their side to keep the lid from sagging too much and this seems like the perfect solution.