Rating: 5 / 5
This is my partner's favorite light weight bivy sack -- the Bozeman Mountain Works VAPR bivy. It does not have the side zipper of the more luxurious model, and weighs about 6.5 oz. -- which is a great alternative to the heavier bivy sacks, like the IDs unishelters at about 40 oz. (but, for the weight, truly weather proof and bombproof).
Stats and info at BackpackingLight.com at:
"From BPL Publisher Ryan Jordan:
This is my favorite piece of gear. It's a perfect mate to a sleeping quilt, and offers more versatility than a sleeping bag with a more water resistant, but less breathable shell. The Vapr Bivy replaces a ground cloth, can be used for winter camping in a tent or snow cave, and the hood can be lifted high with a cord for mid-summer camping in mosquito country."
The NANO version of the VAPR is a couple of ounces lighter, as delivered and can be cut down further, but my partner likes the heaftier fabric in the VAPR. Thus, the NANO is my preferred bivy, as long as I am careful not to damage it on a heavy rock or cinder surface, and hers is the VAPR.
The design and manufacture of the VAPR are good or great -- she, my partner, is looking at removing the bug screening and the little green patch next to where the zippers close on either side.
This bivy gets us into light weight trips using bivy bags, instead of tents. So onward and upward on the gear trail and experimentation to lighten up and get out there more.