Ultralight backpackers and summer travelers who want the smallest practical warm-weather sleeping bag.
WHAT MATTERS
45°F / 7°C lower-limit rating
45°F / 7°C lower-limit rating
850+ fill down insulation
850+ fill down insulation
Listed weight around 12.8 oz.
Listed weight around 12.8 oz.
Compressed volume listed at 2.4 L
Compressed volume listed at 2.4 L
Designed for ultralight backpacking
Designed for ultralight backpacking
GTW TAKE
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THE BAG FOR SUMMER BACKPACKERS WHO WANT THEIR SLEEP SYSTEM TO ALMOST DISAPPEAR
The Spark 45 is built around an aggressive weight-and-volume goal. High-fill-power down, a very low listed weight, and tiny compressed volume make it compelling for ultralight backpackers traveling in genuinely mild conditions. The temperature rating leaves little margin for cold sleepers or volatile mountain forecasts, and the premium lightweight approach is unnecessary for casual car campers.
Best for ultralight summer backpacking where every ounce and liter of pack space matters.
High-fill-power down delivers strong compression compared with synthetic warm-weather bags.
Very low packed weight reduces one of the largest single items in a backpacking load.
Tradeoff: The mild temperature rating provides little buffer when weather or personal sleep temperature runs colder than expected.
