The spark ultralight mummy sleeping bag series is built for every kind of adventure—from lightweight liners for summer getaways to warm, packable bags that'll see you through chilly winter nights. Designed with premium materials and a fuss free focus on performance, these bags keep things simple without skimping on quality. Ultralight doesn't mean cramped the spark's snug mummy shape is designed to keep the heat in, but still gives you enough room to move comfortably after a long day on the trail. Ideal for fast moving, backcountry explorers who don't want to carry a gram more than they need. 850 fill power, rds certifiedgoose down with ultra dry down treatment for improved water resistance in damp conditions10 denier nylon shell and lining10 denier nylon waterproof breathable hood and footboxmummy fit fitted cut with generous footbox and technical hood, to maximise thermal efficiency and minimise bulk and weightspark 7c 45f 1c 30f primary zip 1 2 length 5 with zip plow and two slidersspark 9c 15f 18c 0f primary zip 3 4 length 5 with zip plow and two slidersvertical chest baffles, horizontal baffles lower half and basespark 7c sewn through quilted construction throughoutspark 1c 30fbox wall baffles top half of bag and sewn through quilted construction lower half. Spark 9c 18c box wall baffle construction throughoutspark 7c, 1c 9c standard front draft collarspark 18c double draft collarsspark 7 1 can't be pairedspark 9 18 pairs with women's sea to summit bagsquiltlock system integrates with sts quiltsbest use ultralight backpackingcomes with ultra sil compression bag and storage cellinsulation ultra dry goose down 850 loftmaterials10 denier nylon shell and lining10 denier nylon waterproof breathable hood and footboxshape mummy fit fitted cut with generous footbox and technical hoodbest use ultralight adventuresperformance small pack sizeweight 1113g