The Kelty Cosmic Down 20 is a three-season mummy bag built in Kelty's Short size, fitted for users up to 168 cm, with a men's-specific cut through the shoulders and hips. Manufacturer-rated to 0°C comfort and -6°C limit (with an extreme rating down to -24°C), it uses 415 g of 550-fill-power DriDown duck down — treated to resist moisture the way standard down doesn't — inside a recycled 20D nylon shell with trapezoidal baffles that spread fill more evenly than sewn-through construction.
At 1.06 kg total, it's noticeably lighter than Kelty's colder-rated Cosmic Down 0, which makes sense given the smaller size and higher (less extreme) temperature rating rather than any change in insulation quality. A full draft collar and draft tube seal in warmth at the neck and zipper, and an internal pocket holds small items like a headlamp or phone. Being manufacturer-rated rather than independently lab-tested, actual comfort in the field may run warmer or colder than stated depending on individual metabolism.