I upgraded my Coghlan's orange survival-bag by inserting a Coghlan's space-bag in it and taping them together with duct-tape on the inside.
When repacked, It's about the same size as the original packaging of the survival-bag. Just thought I would pass it along.....

BTW: It would be grate if AMK would also produce a Heatsheet-bag.
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''It's time for Plan B...'' ''We have a Plan B?'' ''No, but it's time for one.'' -Stargate SG-1