What Our Gearhead(R) Experts Are Saying:"This liner is a game-changer for variable weather trips. I toss it in for a little extra warmth on shoulder-season backpacking trips, or use it on its own in huts or warm-weather bivies. The Alpha Direct fleece is incredibly light but still cozy."We bring the Alpha Direct Fleece Sleeping Bag Liner when we want to level up the comfort and performance of our sleep system. Whether we're on the trail, in the back of the van, or crashing at a hut, this liner adds noticeable warmth without adding bulk or weight. The Polartec Alpha Direct fleece is breathable, fast-drying, and incredibly soft-just the thing for cutting morning chills and keeping our sleeping bag cleaner in the process. This liner plays well with right- or left-zip sleeping bags and packs small in its own stuff sack. On warmer nights, it's all we need on its own, and for cold missions, it adds a solid 5 to 10degF of insulation to our setup.