Zippy

Most stuff sacks make you fish around in a dark tube for your headlamp or fumble with a drawcord when your hands are cold. This one opens flat with a waterproof zipper, so you can see everything inside at once and grab what you need without unpacking the rest.

The fabric is Dyneema Composite, the same material used in ultralight shelter floors and dry bags. It stops water completely, tears only if you try to make it tear, and weighs almost nothing. The zipper is waterproof too, so rain, splashes, and condensation stay outside even when the sack is riding in the top of your pack or strapped to the outside of a bikepacking setup.

Three sizes let you match the sack to what you're carrying. The 1L works for a USB battery, cables, and a small repair kit. The 2L holds a water filter, cook kit accessories, or a full toiletry setup. The 3L fits bulkier items like a puffy jacket, ski skins, or a stove and fuel canister together. All three pack down flat when empty and stay rigid enough when full that you can stand them upright in a pack pocket or pannier.

Because the zipper runs most of the way around the perimeter, the sack opens like a clamshell instead of a slot. That means you can lay it flat on the ground, see every item at once, and repack without playing Tetris in the dark. The zipper pull is large enough to grab with gloves on, and the fabric has enough grip that the sack won't slide out of your lap when you're sitting on a log at camp.