Gear Reviews

LL Bean UL Mummy

The best synthetic sleeping bag from the Fall/Winter 2018 Gear Guide.

Brand: LL Bean

Model: UL Mummy


Here in Colorado, we tend to forget that a lot of the country doesn’t see frigid temps in the winter. For those regions—and for hikers everywhere braving wet shoulder-season conditions—this synthetic bag is just the trick. Its design infuses PrimaLoft Gold fill with aerogel, an extremely low-density solid that provides a ton of insulation without a ton of weight. The result: a synthetic bag that’s less than 2 pounds, and packs down to just larger than a football. One tester toted it on a three-week trip through the California Sierra, during which the bag kept him cozy down to 20°F.


The above-average 63.5-inch shoulder and 41.5-inch footbox circumferences result in a semi-rectangular shape rather than a more traditional mummy silhouette, making it one of the more spacious bags we tested. Caveat: Some testers reported chilled feet in subfreezing temps because of the extra room (stuffing a puffy in the footbox helps). 


“It never lost any loft throughout my three-week trip. I’ve seen loft issues with other bags during extended expeditions,” says our California tester. 

Weight: 1 lb. 15 oz.

Temp Rating: 20°F

See more Tents and Sleeping Bags for Winter 2018

See the entire Winter Gear Guide