No cover is completely water proof (it’s not a submarine). This is because water can get in the bed between the vertical edge of the tailgate and the truck. The cover has a seal that goes around the perimeter to prevent water from getting between the cover and the bed rail. Some bed rails are [...]
The approximate weights for the covers are: 5 ½’ bed cover 120 lbs 6 ½’ bed cover 135 lbs 8’ bed cover 165 lbs.
Cover carries a distributed load of 2000 pounds. (Manufacturers do not publish load bearing capacities of their bed rails—especially aluminum beds so please use caution not to overload your truck).