Sea To Summit's new ultralight Spark™ Series of sleeping bags are designed to keep you as warm as possible while minimising packed weight and size. The expedition-sized Spark SPIV is the warmest in the series with temperature rating of -8°C comfort and -15°C Lower comfort.

Constructed using ULTRA-DRY Down™ 850+ loft premium goose down, light-gauge #3 YKK® zip, high-performance 10D nylon shell and 7D lining fabrics, with a contoured mummy shape for efficient insulation and superior performance.

Other features include a full box baffle construction to allow for extra down and reduce cold spots, a full-length zip and a draft tube, full hood and neck collar to keep heat in. An expedition weight mid-winter bag.

Available in regular 880g and long 985g sizes.

• Contoured mummy shape for comfort and efficient insulation
• Expedition mummy bag sizing provides extra space for layered clothing or extra wriggle room
• Responsible Down Standard 850+ Loft Premium Goose ULTRA-DRY Down™ for maximum insulation
• Ultralight 7D and 10D fabrics for minimal weight and packed size
• Vertical chest baffles prevent down movement and cold spots
• Uses a full box baffle construction to accommodate extra down and reduce cold spots
• Full side zip with two sliders provides easy access and extra ventilation options
• Zip draft tube, hood and front neck draft collar to prevent warmth being lost when it's needed
• Includes Ultra-Sil™ Nano Compression Bag for compact storage

• Size: Regular or Long
• Weight: Regular 880g, Long 985g
• Packed: approx 40 x85cm
• Compression: Regular 6.6L, Long 7.7L, 10 to 3.3L sack volume
• Fill: ULTRA-DRY Down™ 850+ Loft premium Goose Down (min. 90% down)
• Fabric: Outer 10D nylon, Inner 7D nylon
• Temp Ratings (EN13537) : -8°C comfort (rating for women), -15°C Lower comfort, -29°C Extreme