The Lost Ranger UL 3N1 15 sleeping bag is part of Big Agnes latest evolution of the Big Agnes Sleep System. This modular ultralight bag design offers just what youd expect: three bag configurations in one simple, yet technical sleep system that stays attached to your pad, so you wont roll off in the middle of the night. Its 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.