Sea to Summit Spark SPII: Compact, Lightweight Sleeping Bag
Downsizing your sleeping bag can pay big dividends in performance off-road.

Sleeping bags are one of the heaviest and bulkiest items you carry while Adventure Riding. If you want your sleeping bag to be both warm and comfortable it tends to be big and heavy. But does it need to be?
Sea to Summit’s Spark series sleeping bags caught our eye for the tiny size they compress down to. The Spark series sleeping bags are some of the lightest and smallest on the market. Everything from the lining to the short zipper and strategic placement of insulation, has been engineered to minimize weight and size. Three different temperature ratings are offered in the Spark line of ultra-compact, lightweight sleeping bags — SPI (46°F), SPII (35°F), SPIII (25°F).
The Spark Series sleeping bags all use a hooded mummy bag design that provides maximum warmth from the least material. Starting with the shell, Sea to Summit utilizes 10D UL Nylon treated with DWR (durable water repellent), to make the bag lightweight, water-resistant and durable. A 1/3-length #3 YKK zipper opens the bag and 15D nylon soft touch, high-density weave material lines the interior, giving it a plush feel and good moisture-wicking properties.
Insulation is provided by 850+ loft European Goose Down, the best quality down available for sleeping bags. Sea to Summit’s “Ultra-Dry Down” treatment allows the fill to repel moisture and dry 60% faster than normal down — helpful if you are constantly moving through a rainy environment.

Also included is a lightweight Ultra-Sil compression bag, made of high-strength CORDURA fabric that allows you to compress the Spark sleeping bag down to a grapefruit-sized package for transport. A mesh storage bag and laundry bag help to keep things hygienic and improve the sleeping bags lifespan back home.
Who Is It For?
For those packing for a long overland journey, a Sea to Summit Spark series sleeping bag can free up valuable space for critical items like spares and tools. And for fast-riding, minimalist-packing, off-road riders, a significant amount of weight and bulk can be trimmed by downsizing your sleeping bag. If you are serious about performance off-road riding, a small sleeping bag may allow you to run a reduced-size luggage setup, saving even more weight and bulk. It’s for those that put a premium on saving weight and space, and don’t mind spending a little extra or sacrificing some comforts in that pursuit.
Our Verdict
We’ve been testing the Sea to Summit Spark SPII in a variety of weather conditions for several months now. With my 6’2″ 215-pound (1.88 meters 97.5-kg) build, I chose the “Long” version and the length is more than adequate. The snug fit around the torso takes some getting used to and getting the bag zipped or unzipped in the dark can be a bit of a challenge. For some with a heavier build, it may be too tight.
The tight fit caused some concern about the zipper’s durability but the #3 YKK zipper is strong for its size. Overall, this lightweight sleeping bag is fairly-rugged and well-put-together but does require some extra caution because of its minimalist design.

The liner has a plush feel on the skin and the down insulation gives it a comfortable feel. However, it’s thinner than your typical lightweight sleeping bag. the SPII is comfortable to sleep in down to around 45°F, below that you start to feel the chill without inserting a sleeping bag liner. Overall, its warmth is consistent with what we would expect from its temperature rating.
While the down insulation allows the bag to compress to a tiny package, it does require some extra care to keep it in good condition. When you come home from a trip, you should immediately take the sleeping bag out of its compression sack and give it a good fluff, then use the included mesh bag for storage or hang it in a cool and dry closet.
The Spark SPII offers an impressive combination of warmth, weight and pack size, but the tight fit and premium price tag make this a purchase some will value more than others. Getting the lightest and smallest sleeping bag possible, can pay off big on your future rides. And if you are dedicated to minimalist packing, it’s well worth it.
- So small, it barely takes up any room in your luggage.
- Interior liner has a nice plush feel on the skin.
- Strategically placed insulation minimizes weight and size.
- Tight fit around the shoulders and elbows for bigger bodies.
- A little pricey for a sleeping bag.
.
For more information on Sea to Summit lightweight camping gear go to www.seatosummit.com.
Specifications
Circumference (Chest, Hip, Foot): 57, 50, 35 in.
Recommended Height: < 6’0″ (1.83 meters)
Compressed Size: 2.9 liters
Fill Weight: 9.9 oz (280g)
Weight: 16.4 oz. (464g)
Temp Rating (Lower Limit): 35°F (2°C)
Temp Rating (Comfort): 44°F (7°C)
Price: $359.00
Sea to Summit Spark SPII (Long)
Circumference (Chest, Hip, Foot): 60, 52, 37 in.
Recommended Height: < 6’7″ (2 meters)
Compressed Size: 2.9 liters
Fill Weight: 10.8 oz (305g)
Weight: 18.0 oz. (510g)
Temp Rating (Lower Limit): 35°F (2°C)
Temp Rating (Comfort): 44°F (7°C)
Price: $379.00
Shopping Options:
Spark SPI (46°) | Spark SPII (35°) | Spark SPIII (25°) |
Notify me of new posts via email
Sea to Summit donates to The Conservation Alliance which is for “human powered” exploration only and has resulted in more riding areas being shut down. Bummer. Maybe they could be prodded to make a donation the Blue Ribbon Coalition as well?
Sea to Summit – Outdoor Gear donates to The Conservation Alliance which is for “human powered” exploration only and has worked to shut down more riding areas not normally considered “wilderness.”
Almost $400 after taxes? Too rich for my blood…