Reader Reviews

Rating: 4 / 5

I have used this bivy for 1 full season now. Compared to the BMW Vapor bivy this overbag has several plusses and minuses.

The advantages

1. No stakeout points. This may seem counterintuitive, but putting the overbag on, and having the sleeping pad outside the setup greatly simplifies the process of getting protection from the wet under a tarp. Staking out the perimeter of the BMW bivy is a little irksome at times. Especially if you're using a groundsheet like I often do.

2. Totally waterproof. Not only that, from my experience there is absolutely no disadvantage to this feature over eVENT or even Quantum. You can sleep in it with slightly wet clothes and in the morning you are actually drier! Under a tarp the dewpoint is usually on the tarp fabric and NOT the interior of the overbag. Exceptional performance for a budget WB material.

3. Good fitting hood. Simple closure but its very effective.

4. At just over 6 oz its very light for a WB overbag. The 12 D outer material seems to be quite durable too (although I wouldn't sleep over bare rock with it!).

Disadvantages:

1. 2 layer design exposes the PU membrane to contaminating skin oils. There doesn't seem to be any way of removing this contamination so this will translate to a shortened service life for this product.

Overall, I'm quite impressed with the product. Pair it with a simple 8 x 10 tarp (like the ID Siltarp 2) and you have a very decent UL shelter that can accomodate 2 VERY easily.

Rating: 5 / 5

Finally a bivy that breathes. It light, inexpensive compared to other bivies. I use it with a tarp, with a marmot helium sleeping bag (not the EQ version but a sleeping bag that breathes as well). It keeps my sleeping bag clean, gives my bag extra warmth, and under wet conditions guarentees I will sleep dry and warm. It has no zipper which is not for everyone but since I'm a cold sleeper more warmth is a plus. When it's hot I sleep in the bivy on top of my sleeping bag. Is it waterproof?
Yes, I put my wife's sleeping bag (it's an older bag that no one uses) in the bivy and put both in the backyard under the sprinkler for 30 minutes, pools of water had puddled but the sleeping bag came out bone dry. I've used this setup for about 2 years, going on 8 to 10 trips each year. I'm quite happy with the Montbell bivy, it weights just 6.5 oz.