I bought this to go over a couple of vehicles I've got stored outside. Don't ask, long story. It can be \"heated\" with a heater, it seems to hold the heat ok. It has windows for ventilation. Easy to use zippers on the front and back for access... big enough for a Ford F350 CCLB, with plenty of room for access. If you need one, this one is priced right, and is the right size. The 17 footer would have been too small... so...