+1 on Alosak bags which I use to for items I in my EDC but don't get into often.
I keep an orange 8 liter Sea To Summit dry bag in my EDC. It rolls up to about a 1" x 10" tube that when the fastek is clipped together makes a fairly small item in your pack.
When I get into a wet situation, urban or back country, I can very quickly ditch all the valuables and electronics into it and its waterproof/air proof. The alosaks, high tech ziplocks can still come undone, its rare though.
I have blown up my Sea To Summit and put it under my shirt and let my 5YO punch me repeatedly and it didn't lose any air.
I liked it so much I picked up a 35 liter for my back pack and it uses e-vent tech, so you can pack it, close it and its water tight. Then you can squeeze all the air out of it to compress and the pores are so small air/water can not get back in. Cool stuff.
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