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  • Sea To Summit - Spark SpI Sleeping Bag: 46 Degree Down - One Color
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  • Sea To Summit - Spark SpI Sleeping Bag: 46 Degree Down - One Color

Sea To Summit Spark SpI Sleeping Bag: 46 Degree Down


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    3 Reviews


    Featherlight comfort for the most minimalist adventurers out there.

    Weighing only 12.3 ounces, the Sea to Summit Spark Spl Sleeping Bag brings the comfort without the weight whether you're an ultralight backpacker, an adventure racer, a touring bicycler, or an alpine climber. Primarily focusing on giving you the lightest bag out there, Sea to Summit stuffed the Spark Spl with 850+ down for the best possible warmth-to-weight ratio that can still keep you nice and toasty in temps down to 45° F. Sea to Summit utilized a 10D ultralight nylon for the shell to keep the bag as light as possible, and then made the lining out of nylon to keep the bag durable. Going beyond just being ultralight, Sea to Summit's Ultra-Dry Down treatment also helps this bag resist moisture to enhance your comfort regardless of the conditions.

    The Spark Spl has a contoured mummy shape to closely fit your body while you sleep. Its full hood wraps around your head to eliminate the possibility of waking up with freezing ears, and the 1/3-length zipper on the left helps maximize warmth when the temps drop down to 23° F. The Spark compresses so small that Sea to Summit had to re-engineer a new compression sack for it, ending up with a sack that fits in the palm of your hand. So when you get this bag, you might be able to stuff your pack with a few extra snacks for the trip even if you're trying to be as minimalist as possible.

    • 45°F temperature rating
    • Ultra-Dry Down 850+ insulation
    • Mummy shape
    • 10D ultralight nylon shell, 15D nylon lining
    • Full hood
    • 1/3-length zipper on left side
    • Total weight: 12.3 ounces
    • Compression sack included
    • Item #STS000F

    Tech Specs

    [shell] 10D nylon, [lining] 15D nylon
    Ultra-Dry Down 850+
    Max User Height
    [regular] 6ft, [long] 6ft 7in
    Shoulder Circumference
    [regular] 57in, [long] 60in
    Hip Circumference
    [regular] 50in, [long] 52in
    Foot Circumference
    [regular] 35in, [long] 37in
    Fill Weight
    [regular] 6.3oz, [long] 7oz
    European Norm Comfort Rating
    European Norm Lower Limit Rating
    Stuff Sack
    Stuff Size
    [compression volume] 1.55 L
    Claimed Weight
    [regular] 12.3 oz, [long] 13.8 oz
    Recommended Use
    ultralight backpacking
    Manufacturer Warranty

    Tech Specs

    • Reviews
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    Great Light and Small Bag - updated

    • Familiarity: I've used it several times

    I was tired of overheating in my 3.5 season (17 F bag) during the summer, so I bought this one. I wanted the lightest, smallest bag available, and this one meets both of those specs, impressively. So far I've only used this for 2 nights in low 60 degree weather but it kept me almost too warm in just a t-shirt and shorts. (I was in a tent without the rain fly on.) I feel confident using this bag down to nights where I expect it to get down to the mid 30s - in that case I'd be wearing more clothing layers. I also plan on using this bag as a liner layer in my 17F bag if I'm expecting temperatures close to 0F.

    UPDATE 2/20/18: I've used this bag several more times in high 40s to mid 50s F degree nights and I still love it. I also used it as a liner in a 19 degree bag with temperatures near 0 F and winds up to 30 MPH in a 3 season tent. The combination kept me very warm.

    Summer bag

    • Familiarity: I've put it through the wringer

    If your like me you try to pack light so that you can carry more snacks. And this bag is light, it weighs just under a pound and compacts to smaller than a Nalgene bottle. But do not use it under 50 or so degrees Fahrenheit. I personally have used this bag in the mid 30's not because of some sort of testing but because I'm dumb & don't watch the weather, and I froze my butt off.

    Summer bag