Sea to Summit Trek Down Sleeping Bag 10

The Sea to Summit Trek Down Sleeping Bag 10 (TkIII) is a three-to-four-season down bag with an EN/ISO 23537-tested comfort of -5°C and a limit of -12°C. The fill is 700 g of 650 fill power hydrophobic-treated duck down, with more down placed in the top of the bag (a 60/40 distribution) where insulation matters most. At 1,190 g, it offers a solid balance of temperature range and weight. Vertically oriented baffles keep the down in place, while a 30D nylon ripstop shell and 20D nylon liner add abrasion resistance. A two-way, full-length zipper opens the bag completely flat, a draft collar and draft tube limit heat loss, and the contoured 3D hood follows the shape of the head well. Sized for users up to 183 cm, it includes an internal security pocket and can be coupled with a second bag into a double. The down is RDS-certified. It's a solid choice for autumn and winter trekking in temperate regions where real cold-weather performance is needed without stepping up to an expedition bag.