Sea to Summit Traverse Synthetic Sleeping Bag 15

The Sea to Summit Traverse Synthetic Sleeping Bag 15 is a three-to-four-season synthetic bag with a manufacturer-rated comfort of -4°C and a limit of -9°C. Insulation comes from a combination of Thermolite fill and WaveLoft construction aimed at maximizing warmth for the weight; at 1,440 g, it's a heavier, more rugged bag where performance and durability take priority over minimal weight. Its defining feature is a triple-zipper system — a full-length zip on the left, a half-length zip on the right, and a separate foot-box zip — which lets the bag open completely flat as a blanket and lets you dial in ventilation as temperatures change. A 30D DWR nylon shell and 100% polyamide liner, together with a draft collar and draft tube, add further protection against cold air infiltration. Sized for users up to 182 cm, it can be coupled with a second bag into a double, packs into its included compression sack, and uses PFC-free treatment. It suits autumn and spring trekking and camping where the moisture resistance of synthetic fill is the priority.