Sea to Summit Spark Ultralight 18F Sleeping Bag

$489.00 to $509.00
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Designed for late spring to early fall use, the Sea to Summit Spark Ultralight 18F sleeping bag is a lightweight pick for ounce-counting backpackers. It serves up easy ventilation and cozy comfort.

  • Features

    • 850-fill-power down provides cozy warmth
    • Baffles in the torso area keep insulation in place; sewn-through construction in the leg area helps keep this bag lightweight
    • 10-denier shell and 7-denier liner materials deliver an impressively light weight and compact packed size
    • Full-length side zipper with 2 sliders offers easy ventilation options
    • Includes lightweight Ultra-Sil™ compression bag and storage cell


    Many sleeping bags are rated for temperature by an independent testing protocol. REI and the broader industry now use the International Organization for Standardization (ISO) 23537 protocol, which improves on the older European Norm (EN) 13537 standard; you may still see older items in our assortment that were only EN tested. With either protocol, each bag gets a Comfort (or T-Comfort) rating and Lower Limit (or T-Limit) rating. The Comfort rating is the lowest temperature at which the bag will keep the average "cold sleeper" comfortable, and the Lower Limit rating is the lowest temperature at which the bag will keep the average "warm sleeper" comfortable. Ratings are based on a person wearing one long underwear layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38. Many brands use the Comfort rating for women's bags and the Lower Limit rating for men's and unisex bags. Everyone's body and sleep comfort differ, and conditions of use (posture, clothing, sleeping pad R-value, wind, humidity, etc.) affect total insulation, so EN and ISO ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth.
    View all Sea to Summit Men's Sleeping Bags
  • Technical Specs

    Best Use


    Tested Lower Limit

    18 degrees (F) - EN

    Tested Comfort

    29 degrees (F) - EN

    Temperature Rating (F)

    18 degrees (F)

    Temperature Rating (C)

    -8 degrees (C)


    Regular: 1 lb. 8 oz.

    Long: 1 lb. 10 oz.




    10-denier nylon

    Zipper Location


    Insulation Type


    Water-Resistant Down



    Ultra-dry down

    Fill Weight

    Regular: 14.4 oz.

    Long: 1 lb. 1.6 oz.


    7-denier nylon

    Sleeping Bag Shape


    Fits Up To (in.)

    Regular: 72 inches

    Long: 78 inches

    Shoulder Girth (in.)

    Regular: 61 inches

    Long: 64 inches

    Hip Girth (in.)

    Regular: 53 inches

    Long: 56 inches

    Stuff Sack Size

    6 x 14 inches

    Stuff Sack Volume

    6 liters

    Compressed Volume

    Regular: 4.6 liters

    Long: 5.4 liters



  • Reviews
    105 reviews with an average rating of 4.6 out of 5 stars

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