Sea to Summit Spark Ultralight 28F Sleeping Bag

This product is not available.

Shop similar products

Designed to keep you as warm as possible while minimizing packed weight and size, the Sea to Summit Spark Ultralight 28F sleeping bag is lightweight and technical for your industrious adventures.


  • Super lightweight 7-denier and 10-denier fabrics offer minimal weight and packed size
  • 850+ fill-power Premium Goose UltraDry Down™ is certified to the Responsible Down Standard (RDS) and provides maximum insulation value
  • Contoured mummy shape provides comfort and efficient insulation
  • Vertical chest baffles prevent down migration
  • Note: This bag is not designed to zip with another
  • Includes lightweight Ultra-Sil™ compression bag and storage cell


Temperature ratings are intended as a guideline to help you compare products, rather than a guarantee of warmth, since many different factors contribute to your comfort while you sleep. Backpacking bags are typically rated for temperature according to an independent testing protocol—currently International Organization for Standardization (ISO) 23537, though some older items followed European Norm (EN) 13537. Testing is based on a person wearing one base layer and a pair of socks, sleeping on an insulated surface with a minimum R-value of 5.38.

Each bag then gets 2 ratings: 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. Some brands determine their own temperature rating by aligning to the Comfort rating for women’s bags, to the Lower Limit rating for men’s bags, or somewhere in the middle for nongendered bags.
View all Sea to Summit Backpacking Sleeping Bags

Technical Specs

Best Use


Tested Lower Limit

28 degrees (F) - EN

Tested Comfort

38 degrees (F) - EN

Temperature Rating (F)

28 degrees (F)

Temperature Rating (C)

-2 degrees (C)


10-denier nylon

Zipper Location


Insulation Type


Water-Resistant Down



850+ UltraDry Down


7-denier nylon

Sleeping Bag Shape


Stuff Sack Size


Stuff Sack Volume


Compressed Volume





Down certified to the Responsible Down Standard (RDS)

154 reviews with an average rating of 4.6 out of 5 stars

Loading Reviews...

Questions & Answers

Loading Questions...