It is for backup/emergency only. A sleepingbag is too big. The more sleeping gear i carry, the more likely i'll have to use it. I personally prefer single person models, but the guides want us to carry the double versions.

Requirement:
- Light weight and small (less than 500 grams)
- Waterproof, breathable is not required.
- Durable enough to survival 2 nights, but does not have last longer.
- proper closing opening
- 60 euro or less (~$70), shipping included
- vents would be nice.

I was thinking of turing two heatsheets in to a large bag and add a drawstring opening. I just haven't found a good tape, which i trust enough for the job. (to bulky, not sticky enough, to wide, loosing stickyness with heat and time)