Way back when someone (think it was Doug)
posted a preliminary review of these (pasted in below). Has anyone had a chance to do a more thorough one since?
qjs

'ITW MILITARY PRODUCTS

ITW specializes in military accessories, including fasteners and enhancements for military webbing, especially for the MOLLE system. Normally they would not be of interest to ETSers unless you built your own packs and pouches for your bug-out-bag, but this year they have something that may be of interest – the X-Proof Protective Bags.

While they look at first pass to be large Zip-Loc bags, these bags appear built for the field and not the fridge. They have heavy-duty double locs at the top of the bags, and the bags themselves seen to be of a much heavier weight of plastic (double the mils, perhaps?).

The X-Proof Protective Bags come in four sizes: the “Administrative” size, approx. 8” x 10”, (which the ITW spokesman said was sized to fit in the cargo pocket of military BDU trousers); two “Compression” sizes, approx. 14” x 20”approx. 18” x24”, and a large “ruck” size, made as a liner for a military rucksack or backpack. The latter also has a pleated bottom (to allow for maximum use of the bag) and simple carry handles on top. The “Compression” sizes have a simple one-way air valve in the bottom of the bag that allows you to crush the bag when closed to get all of the air out.

That’s the good news. Now the not so good: We tried the one of the samples with the one-way valve at the hotel (several days of dirty shirts), and, yes, it crushed down beautifully; but it returned to it’s non-compressed state within 15-20 minutes. The small “Administrative” size, however, kept a T-shirt nicely compressed for more than 24 hours.

As these are new products, and the samples provided us may be early runs, some glitches are to be expected. Also, we may not be using the compression bag correctly (unlikely, but still…), and one test in a hotel room is not definitive (more tests now that we are home). But even in their uncompressed state, X-Proof Protective Bags appear to protect your gear in the field better than your average sealable bag designed for the kitchen.'

If they're as 'good' as the Ziplock brand vacuum freezer bags, don't bet your firemaking stuff on them.

Sue

If you want something a bit tougher than ziplocks, try Aloksaks. They do very well for me, and they are eually convenient - just pricy.

I have had a similar experience with space bags. They compress down pretty well but air slowly seeps back into them over time.