Now, there’s a sleeping bag to join them: the Fly Creek UL25. With a similar emphasis on superlight, super-efficient performance, it'll help to keep your trail weight to a minimum.

The Cedar Ridge Alloy 20 Sleeping Bag is just $42 during REI's massive outlet sale until April 28. Shoppers say it's very warm and feels like a comforter.

Marmot Always Summer 40 Sleeping Bag, $105 (was $199) at REI Courtesy of REI This sleeping bag has a snug mummy design, weighs under 2 pounds, and is filled with a water-resistant 650-fill-power ...