UltraLite
Mummy (w/ full collar)
- Weight, 6′0″
- 1 lb 13 oz820 g
- Insulation
- 850+goose down
- Shell
- 12D ripstop nylonExtremeLite
How warm is it, really?
- EN/ISO extreme
- -21°F
- EN/ISO limit
- 14°F
- EN/ISO comfort
- 25°F
- WM rating
- 20°F
Our rating usually falls between the EN/ISO “limit” and “comfort” figures, and assumes a well-insulated pad (about R 5.0 in the cold), dry base layers and socks. How we rate our bags.
UltraLite – Three-Season Ultralight Sleeping Bag
The UltraLite is a three-season ultralight sleeping bag built for backpackers who want premium warmth without added weight or volume. Weighing just 1 lb 13 oz, it delivers award-winning performance for everything from weekend trips to thru-hikes.
This bag uses 850+ fill power ethically sourced goose down for excellent loft and compressibility. The down insulation provides reliable warmth for cool nights across spring, summer, and fall conditions.
The ExtremeLite™ shell fabric is ultralight, breathable, and tightly woven. It helps keep moisture out while allowing internal humidity to escape. It’s one of the lightest, most efficient shell fabrics available today.
The efficient mummy shape improves thermal retention while minimizing unnecessary material. A full down-filled draft tube seals in body heat along the zipper. The hood cinches tight for added warmth when the temperature drops.
The UltraLite is ideal for trails like the John Muir Trail, the Colorado Trail, or any high-mileage route where performance matters. It packs small, sleeps warm, and holds up to repeated use.
Whether you’re chasing ultralight efficiency or dependable comfort in the backcountry, the UltraLite is ready to go the distance.
Proudly made in the USA, the UltraLite is one of Western Mountaineering’s best-selling and most trusted bags. It’s light enough for fast missions and warm enough for real nights in the mountains.
When you need one bag to do it all—this is it.
Features
- Filled with 850+ Fill Power ethically-sourced premium goose down
- Continuous baffles allow you to shift down for more insulation in colder weather
- Full-length #5 YKK zipper provides a smooth, easy unzipping experience while saving weight
- Insulated Draft Tube blocks cold air and keeps the torso better insulated
- Breathable 12 denier ripstop nylon outer shell makes bag ultralight yet durable
- Fully insulated draft collar seals in inner heat without adding much weight
- Comes with ultralight stuff sack and breathable storage bag
- 1 lb 13 oz. Total Weight
Specifications
- Shape
- Mummy (w/ full collar)
- Temp Rating
- 20°F
- Fill
- 850+ Power Goose Down
- Color
- Royal Blue/Black
- Country of Origin
- USA
- Fabric
- 12D ripstop nylon
- Loft
- 5.5" in
| Length | Inside Girthshoulder / hip / foot | Fill Weight | Total Weight | Stuff Size |
|---|---|---|---|---|
| 5'6" | 59"/51"/38" | 15 oz | 1 lb 12 oz | 7"x13" XS |
| 6'0" | 59"/51"/38" | 16 oz | 1 lb 13 oz | 7"x13" XS |
| 6'6" | 60"/52"/38" | 17 oz | 1 lb 15 oz | 7"x13" XS |
