I was having trouble getting my synthetic -30 winter bag into the bag comparment of my pack. This compression sack is ideal for the job. Rectangular construction so it fits the inside of the pack better than a cylindrical sack. Four 3/4" compression straps, one with a quick release buckle, so you don't have to dig your fingernails into the rock hard sack to get it open. Lightweight fabrics all around. Not waterproof, as I use it for winter only, and there is no water, but a trash bag does wonders for waterproofing if the need arose. Nice handle on the backside that is easy to grab, even with mittens, instead of an annoying fold of fabric that is hard to hold on to. Seriously strong construction where it counts: triple stitched seams and bar tacks all around.