SOL Thermal Bivvy
Here's my review of Adventure Medicals' Thermo-Lite Bivy:
Price Paid: $26.50
With this bivvy sack, I turned a synthetic filled Wenzel mummy bag, rated around 30 degrees F into a really cozy mountain sleeping bag.
I slept inside this combination in a winter expedition at around 5800 feet in last December. The temp was 17 degrees outside the tent and no part of my body was cold during any of the two consecutive nights.
I also used the bivvy without additional sleeping bag in last summer, it had again done the trick, although I awoke towards the moning shuddering a little because I was somehow half way out of the bag. Stitching around the velcro should be sturdier, though.
All in all, I recommend this bivvy to any hiker, backpacker, biker, etc.
Where to Buy
Here's what other sites are saying:
The Adventure Medical SOL Thermo-Lite Bivy is your go to gear for emergency situations. The Thermo-Lite is a bivvy sack that is ideal as a light weight replacement for your sleeping bag when temperatures are above 50F/9C and an excellent emergency survival shelter for winter time activities. Waterproof and windproof protection.
Whether your day hike has turned into an overnight survival situation, the power goes out in your home in cold weather, or your car is stranded in a snowstorm, the SOL Thermal Bivy will help keep you warm and protected from the elements. Can also be used as a warm-weather sleep system.
The SOL Thermal bivvy can be used as substitute for a sleeping bag on warm-weather adventures or as an emergency survival bivvy for wintertime activities. Tough 4-ply fabric is windproof and waterproof; material reflects up to 80% of your body heat back to you. Works well as a lightweight substitute for a sleeping bag when nighttime temperatures are 50degF or above. Foot vent and large opening at the top keep you from getting too hot. Reusable SOL Thermal bivvy comes packed in a stuff sack; packs down to 6.5 in. x 7 in.
The lightweight Adventure Medical Thermal Bivvy reflects 80% of your body heat right back at you, so you can stay warm whether you're backpacking in summer weather or 'enjoying' an unexpected night or two in the woods. The non-woven material is stronger and more durable than typical Mylar survival blankets, so you can use it more than once.