$549.00 to $569.00
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A lightweight, compact sleeping bag for use across 3 seasons, the Sea to Summit Spark Ultralight 5F features a full-length zipper with 2 sliders to provide extra ventilation when the weather warms up.

  • Features

    • Functional for 3 seasons of use; hardy adventurers may even push the limits into early or mid-winter
    • 850-fill-power down provides cozy warmth
    • Fully baffled construction keeps insulation in place
    • 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 hat, 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

    5 degrees (F) - EN

    Tested Comfort

    18 degrees (F) - EN

    Temperature Rating (F)

    5 degrees (F)

    Temperature Rating (C)

    -15 degrees (C)


    Long: 2 lbs. 3 oz.

    Regular: 1 lb. 15 oz.




    10-denier nylon

    Zipper Location


    Insulation Type


    Water-Resistant Down



    Ultra-dry down

    Fill Weight

    Long: 1 lb. 8 oz.

    Regular: 1 lb. 6.4 oz.


    7-denier nylon

    Sleeping Bag Shape


    Fits Up To (in.)

    Long: 78 inches

    Regular: 72 inches

    Shoulder Girth (in.)

    Long: 64 inches

    Regular: 61 inches

    Hip Girth (in.)

    Long: 56 inches

    Regular: 53 inches

    Stuff Sack Size

    7 x 16 inches

    Stuff Sack Volume

    10 liters

    Compressed Volume

    Long: 7.7 liters

    Regular: 6.6 liters



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