Whether we're setting up camp in the trunk of the car or pulling into our favorite secret campsite for the weekend, the Sea To Summit Trek Sleeping Bag keeps us warm and toasty all through the night. The semi-rectangular shape of the bag offers generous space for the tossers and turners, and the Free Flow zip system allows us to open up key parts of the bag for more space and increased ventilation. The 650-fill down insulation is treated with Ultra Dry Down treatment to repel light moisture and maintain lofty warmth in damp conditions.