For committing expeditions, the Mythic offers premium performance at a premium price. There’s 900-fill goose down, and a clever construction that saves weight by using chevron-shaped baffles to hold down toward the center without using extra interior fabric. But the thermal innovation comes from a titanium lining misted onto the inside of bag at fabric level so it never wears off (unlike other, glued metallic interior treatments that can peel). In theory, it’s like having an onboard space blanket that is soft to the touch and silent. Rab claims a boost in thermal efficiency up to 14°F. Our warm sleepers noticed the extra warmth, but cold sleepers were mixed on how much of a bump the lining provided. It’s slightly-roomier-than-standard dimensions pack down to the size of a canteloupe.
$650; 1 lb. 5 oz.; 20°F; one size