Bed cover?

[toku58]

I am looking for a bed cover. Up for consideration is the lund tri-fold Or the Extang tri-fold. Reason: easy to take of if needed. (and store) Any way I have noticed on my truck that the side rails are about an inch higher that the tailgate, and the front of the bed? How is this issue addressed with the bed covers? Do they use some type of cheap foam fillers, for the gap? Or is the covers designed for this difference in bed rail height?

[PiercedTiger]

My BAKFlip cover sits between the side rails so it's actually flush with the top of the tailgate. You'll want to add those extra D-Rings first if you get this cover or a similar one since they cover the factory cargo rail system. It doesn't remove easily. Well, it does if you remove the 2 bolts and want to try getting the gas struts lined back up again. They are a bit of a PITA to hold down and line the bolts back up at the same time. So I don't plan on removing mine. It gets out of the way pretty good anyway as it is.