Platy 2-Liter Ultralight Collapsible Backpacking Water Bottle

Two liters of capacity for 36 grams at a modest price is a trade almost every lightweight backpacker makes eventually. Rolled empty, the Platy Bottle disappears into a pocket, so you can carry the capacity for a dry stretch or a waterless camp without paying for it on the days you do not need it. It also threads onto common filters, which makes it a serviceable dirty-water bag. The limitations are the ones that come with a flat plastic bag. Packed against a stove or a tent stake it abrades and eventually splits at a crease, and a failure means a soaked sleeping bag rather than a leaky bottle. The narrow opening makes it slow to fill from a shallow trickle and effectively impossible to dry inside - expect it to sit on the counter at home for two or three days. The cap is not tethered, and a lost cap is a lost bottle.