The Spark is engineered to keep you warm at the lightest weight and smallest compressed size. Designed with premium materials and a fuss-free focus on performance, these bags keep things simple without skimping on quality. Suitable for lightweight liners and summer getaways as well as warm, packable bags that’ll see you through chilly winter nights.

Ultralight doesn’t mean small; 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-certified
• Goose Down with Ultra Dry Down treatment for improved water resistance in damp conditions
• 10-Denier Nylon shell and lining
• 10-Denier Nylon waterproof-breathable hood and footbox
• Mummy Fit: Fitted cut with generous footbox and technical hood, to maximise thermal efficiency and minimise bulk and weight
• Spark 7C/45F & 1C/30F Primary zip - 1/2 length #5 with zip-plow and two sliders
• Spark -9C/15F & -18C/0F Primary zip - 3/4 length #5 with zip-plow and two sliders
• Vertical chest baffles, horizontal baffles, lower half and base
• SPARK 7C sewn through quilted construction throughout
• SPARK -1C/30Fbox wall baffles top half of bag and sewn through quilted construction lower half
• Spark 7C, -1C & -9C Standard front draft collar. SPARK -18C Double draft collars
• Spark 7 & -1 can't be paired. Spark -9 & -18: Pairs with Women's Sea to Summit bags.
• QuiltLock System integrates with StS quilts
• Best Use: Ultralight Backpacking
• Comes With: Ultra-Sil compression bag and storage cell
• Insulation: Ultra-Dry Goose Down 850+ Loft
• Material(s):10-Denier Nylon shell and lining
• 10-Denier Nylon waterproof-breathable hood and footbox
• Shape: Mummy Fit: Fitted cut with generous footbox and technical hood
• BEST USE: Ultralight adventures
• PERFORMANCE: Small pack size
• WEIGHT: 730g