Sea to summit event compression sack - Sea to Summit eVent Compression Dry Sacks

This is a light "waterproof" (not intended for submersion) compression sack. The top has to be rolled at least 3 times away from you, and then the top plastic buckle ends are snapped together towards you. Has 4 compression straps to cinch down once you put the top on. The eVent is supposed to let air out as you compress the sack, but not allow water in. The large seems to work well for holding my WM Badger 7 foot sleeping bag. I have another compression sack that has a cord that tightens the top. Cord tightening is far easier than stuffing the bag in and rolling and buckling while the bag is trying to expand out. The cord types don't stop water as well though, so the rolling and buckle works to keep water out.