The medium was the perfect size, zipper is tight and fairly easy to use. Just go slow around the corners. The water resistant material is amazing and I can fit a few outfits in the medium cube. Didn't think I need another cube but this was very useful and easy to push the air out once almost zipped.

Keeps the elements, dirt, dust, and grime out to keep your conents safe & clean. While not submersible, it keeps your contents clean & dry from melting snow, falling rain, splashing mud, paddle spray, and fish flopping around the boat. As a size reference, the medium fits a six pack of cans with space left on the end. The zippers are shielded and have nothing to snag on. The material cleans easy with just a wet rag and returns to looking like new. One size is not enough; you'll want multiples of each size for packing flexibility while keeping your things safe & dry regardless of where your adventure takes you!

these fit great in a backpack, layering up and keeping my need for a pack cover low. Easy to see what's inside, grab out of the top of the pack, and actually use (i.e. pack inside). The only thing I wouldn't use these for is packing a bag/quilt or tent, just based on how I store those.