AKA U.L. Sleeping Bag Cover
http://www.montbell.us/products/disp.php?p_id=2321024This little gem holds a lot of promise, but I find in practice that it fails to live up. Or perhaps I'm just expecting too much. It works OK as a ground sheet, and I appreciate its extra puncture resistance beneath my Neoair Xlite, but I have found that I cannot put the pad and bag both inside the sack for protection from dew. There's not enough room, I compress the down, and I get cold.
Since it has no zip, it's all or nothing. I can't really vent it. Thus most nights I use it as an expensive (and probably fragile) groundsheet, and as a bivy it's generally emergency gear to be used in case of real rain, in which case the pad goes on the outside (ends up dirty, more likely to puncture), I still have to be a bit more careful to preserve loft, and the bag does get wetter from my sweat.
Do most of you just leave it packed unless you expect actual rain? Do you use it as a ground sheet, maybe only if the ground is soggy?
