Review: Sea to Summit Spark Down Sleeping Bag

Summer nights in Montana can get chilly—especially up in the alpine. But who wants to carry a winter sleeping bag 3,000 feet up a mountain to a remote alpine lake? I do, so long as it weighs only 2lbs., 10.5oz. That happens to be the weight of the Spark Down 0-Degree Sleeping Bag from Sea to Summit. This impressive bag features 850-fill power goose down—treated with a water-resistant chemical—wrapped in a 10D nylon shell. For those keen on the nitty-gritty technical specs, 10D is awfully thin for a sleeping bag. But as outdoor textiles become stronger and more durable, it's likely comparable to a fabric twice as thick from just five or ten years ago. You’d be hard-pressed to find another commercially-available sleeping bag with similar warmth and weight as the Spark Down.

In terms of comfort, the bag is cut with a little wiggle room so it doesn’t feel claustrophobic. The toe box is fairly loose as well, which is nice for drying out damp socks or extra layers at night. Finally, an oversized zipper provides snag-free use, and a tight hood and collar prevent cold drafts from sneaking in. The only real drawback is the price ($679 for the Large Long size). But as anyone who has spent a night shivering for ten hours can attest, a good down sleeping bag is worth its weight in gold in the mountains.

Available at seatosummit.com.