Spark SpI 40F

$359.00 - $379.00


Ultralight and super-compact with 850+ ULTRA-DRY Down

The Spark 40F is an ultralight down bag that packs down super-small for use as a liner or standalone summer bag. The Spark uses premium materials, including ULTRA-DRY Down 850+ Loft Loft, and no-frills design to provide cutting-edge performance for backpacking, bikepacking, and travel. Ultralight does not mean ultra-tight: The Spark sleeping bags are snug but still have adequate girth for the performance-oriented backcountry user.


Brand Name:
Sea to Summit
Temp Rating:
40° F
Seasonal Usage:
Temp Rating Celsius:
4° C
Bag Style:
Fill Weight:
Regular: 6.3 oz / 180 g
Long: 7.2 oz / 205 g
Gray / Yellow
ULTRA-DRY Down 850+ Loft; RDS-certified
Regular: 12 oz / 340 g
Long: 13.6 oz / 385 g
Bag Length:
Regular: fits users up to 6 ft / 183 cm
Long: fits users up to 6 ft 4 in / 192 cm
Circumference at Chest:
Regular: 59 in / 150 cm
Long: 62 in / 158 cm
Circumference at Hips:
Regular: 51 in / 130 cm
Long: 54 in / 138 cm
Circumference at Foot:
Regular: 35 in / 88 cm
Long: 38 in / 94 cm
Bag Shell Material:
10D Nylon
Bag Stuff Size:
1.5L volume when compressed using included compression sack
Other Features:
• ULTRA-DRY Down 850+ Loft 90% Down Cluster Premium Duck Down certified Responsible Down Standard (RDS)
• 10D shell and 7D liner materials help to achieve the incredible lightweight and compact packed size
• Sewn-through construction minimizes weight
• Vertical baffles on chest optimize position of down to prevent it moving during use
• 1/2 zip with single slider keeps weight to a minimum
• Updated sizing provides extra room for both shoulders and hips while maintaining insulation efficiency
• Includes lightweight Ultra-Sil™ compression bag and storage cell

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