REI Waterproof Bivouac with Matching Sleeping Bag An older bivy with some versatile features that I haven't seen in others. Pros * Waterproof * Bug proof * Lightweight * Increases warmth * Cinches down tight Cons * Keeping rain out of head hole can be tricky. You need to be aware of the position of your head. Setup: Since there are no poles or stake out points, you just throw the bag on the ground and crawl in. Weather Resistance: Keeps water out really well except for the hood hole. It works well as long as you position yourself right, cinch tight, and don't toss and turn too much in your sleep. If the sack is used in conjunction with a small head tarp, there aren't any issues. Ventilation: The hood hole offers great face ventilation. The bag itself is impermeable 2/3 the way down. Room: There is ample room in this bivy for a thicker cold weather sleeping bag with lots of loft. I once stuffed 2 sleeping bags and a sleeping pad in it on a really cold night. It was a squeeze but I stayed really warm. Packability: Packs down to approx 5" x 11". It weighs approximately 1lb 12oz. Ease of use: The bivy has 4 zippers so no matter what way you are turned, you have zippers to get you in and out of the bag. For added protection, you can snap the bag shut as well. The hood has a good head cover that leaves your face exposed. You can roll the hood up and snap it down to give you a nice opening. There is a cinchable bug net that snaps over the head hole. The hole works very well at keeping condensation out of the bivy.