Sea to Summit Trek TkIII 10 Sleeping Bag

$379.00to $399.00
Color: Navy Blue
please select a Size
Choose a shipping method

With a shape that gives you room to move and 650-fill-power down, the Sea to Summit Trek TkIII 10 sleeping bag is a warm choice for 3-season adventures, from backyard campouts to multiday treks.

  • Features

    • 650+ loft Ultra-Dry Down™; down is certified to the Responsible Down Standard (RDS)
    • Full-length YKK #5 main side and foot zippers provide superior ventilation and allow the bag to be used as a comforter
    • Shaped hood and oversize zipper draft tubes seal in warmth and keep cold out
    • Internal pocket is ideal for a phone, GPS device or other valuables
    • Includes a lightweight Ultra-Sil™ compression bag and storage cell
    • Forms a snug double sleeping bag by zipping to any Altitude, Journey or Venture sleeping bag (not included)
    • Sea to Summit guarantee is offered for the lifetime of this product; see manufacturer's website for details


    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 Backpacking Sleeping Bags
  • Technical Specs

    Best Use


    Tested Lower Limit

    10 degrees (F) - ISO

    Tested Comfort

    21 degrees (F) - ISO

    Temperature Rating (F)

    10 degrees (F)

    Temperature Rating (C)

    -12 degrees (C)


    Regular: 2 lbs. 10 oz.

    Long: 2 lbs. 14.2 oz.


    30-denier nylon

    Zipper Location


    Insulation Type


    Water-Resistant Down



    650-fill-power Ultra-Dry premium down

    Fill Weight

    Regular: 1 lb. 8.7 oz.

    Long: 1 lb. 11.5 oz.


    30-denier nylon

    Sleeping Bag Shape


    Fits Up To (in.)

    Regular: 72 inches

    Long: 78 inches

    Shoulder Girth (in.)

    Regular: 60 inches

    Long: 64 inches

    Hip Girth (in.)

    Regular: 57 inches

    Long: 62 inches

    Stuff Sack Size

    8 x 18 inches

    Stuff Sack Volume

    14 liters

    Compressed Volume

    Regular: 8.4 liters

    Long: 10 liters




    Down certified to the Responsible Down Standard (RDS)

  • Reviews
    25 reviews with an average rating of 4.4 out of 5 stars

    Loading Reviews...
  • Questions & Answers

    Loading Questions...