Dont expect a waterproof cover with Calmark. The problem I had is it allowed too much water to seep thru and collect under the cabover and at that point the cover would belly up with water. Of course that part of the cover appeared to be waterproof and held the water. Sold it and put up a metal carport.
2009 Silverado 3500 dually D/A, Supersprings, Stable Loads, Bilsteins, Hellwig Sway Bar.
2010 Arctic Fox 1140 DB, 220 watts solar, custom 4 in 1 "U" shaped dinette/couch, baseboard and Cat 3 heat, 2nd dinette TV, cabover headboard storage, 67 TC mods