Sea to Summit Spark Ultralight -9°C Sleeping Bag Features_Twist Lock the ultralight Helium Bivy is

the ultralight Helium Bivy is 14% lighter than its last generation

The ideal layer for shoulder season hikes or early morning summer starts

The map shows the walk trail and camp sites set in a full sized topographic map

enhancing ease of use without compromising on durability

AirZone cutout space

Sea to Summit Spark Ultralight -9°C Sleeping Bag Features_Twist Lock the ultralight Helium Bivy isIf you're counting grams, but still count on a great night's sleep, the Spark may be the right bag for you. Filled with RDS certified 850+ fillpower goose down treated with a non PFC Ultra Dry Down treatment, the Spark is constructed with a technical hood and zipper draft tube to retain warmth. Comfort comes from a super breathable 10 denier liner fabric, while a 10D shell with a non PFC DWR plus a highly water repellent hood and footbox fabric shed