The Lost Ranger UL 3N1 0° sleeping bag is part of our latest evolution of the Big Agnes Sleep System. This modular ultralight bag design offers just what you’d expect: three bag configurations in one simple, yet technical sleep system that stays attached to your pad, so you won’t roll off in the middle of the night. It's the only bag you need for 3-season camping, backpacking and everywhere in between. These ultra-lightweight, down-fill bags deliver comfort and versatility no matter your sleep style or temperature preference.