Thermos Mountain FFX 750 ml

The Thermos Mountain FFX 750 ml is a stainless steel vacuum flask sized for a full day of hydration for one person, or for sharing at a group stop. Double-wall vacuum insulation keeps drinks hot for 30 hours and cold for 32, so a flask filled in the morning stays at temperature for essentially the whole day on the trail. The cap opens and closes with a half turn rather than a full unscrew, which is handy one-handed when the other hand is occupied with a pole or a map. There is no carry loop or carabiner attachment, so it is meant to live in a side pocket of the pack rather than clip on externally. At 360 g it belongs with gear for alpine days and overnight bivouacs rather than ultralight base-weight builds, where the extra grams would register. The stainless steel is BPA-free, the seal resists leaks even tilted inside a pack, and the material tolerates boiling water or hot tea without issue.