The MSR AC Bivy is an impressively lightweight bag that offers great protection with maximum breathability. A great spring to autumn bivvying choice.
When weight and space really count, the AC Bivy shelter is the best and most efficient way to get the all-condition protection you need. Maximum waterproof-breathable fabric coverage on top delivers the best possible breathability, while an extra-tough floor with 10,000mm DuraShield™ coating lets you rest confidently through anything. A zippered shoulder entry with mesh allows excellent bug-free ventilation and makes the bivy shelter easy to get into and use while sitting up.
The 2016 AC bivy is lighter, more breathable and more waterproof than it's predecessor. It's hard to get past just how thin the material feels, but MSR tells us that the AC-Bivy boasts extra tough durability.
The mesh screen that lets in air but keeps bugs out will certainly be appreciated come midge season; but although this vented area can be covered, there's no way to fix this closure, so wind and rain could find their way inside the bag in really bad weather. So maybe not quite 'all conditions' then, but still an impressively lightweight bag.
- Reviewed by Ultralight Outdoor Gear