. "To assure that rain or other forms of water do not enter the area between the cover 12 and the window 16, the top 24 is sized larger than the opening 19 in the base 18 through which the vent structure 20 pivots, and if desired, a rubber seal 50 can be positioned about and along the edge of the undersurface 52 of the top 24 to assure that nothing can move past when the top 24 is placed in a closed" . . .