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Lost Ranger UL 3N1 15°

3 bags, 3 seasons, 3N1

The Lost Ranger UL 3N1 15° 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.
100% Guarantee


Our top priority is to provide customer service as stellar as the award-winning products we create. If one of our products does not perform to your satisfaction, contact our customer service team and we will help you find gear that fits your needs.
Lost Ranger UL 3N1 Series

Pad Cinch System

The Pad Cinch System is designed to help keep you and your bag on your pad all night long, no matter how much you toss and turn. 

The drawstring connects your bag to the pad while a middle securement feature provides extra stability. It is adjustable to fit any pads sized between 20”x66” - 30”x78”.

3N1 Sleep System Sleeping Bags

Everything you need to know… 

1. Keep your head snug and warm using the inner bag with jacket-style hood 

2. Three-quarter, anti-snag zipper 

3. Pillow barn on pad sleeve keeps your pillow tucked in 

4. Hand tuck pockets at the top of outer bag

5. 650 fill DownTek™ repels water while maintaining insulating value with bluesign® certified PFC-free water repellent chemistry

6. Two-way zippers on both sides for venting and easy access from top or bottom

Specs + Sizing


3N1 System Bags offer three bag configurations for temperature versatility with a technical, roomy sleeping space that keeps you on your pad throughout the night 

Ultralight, durable materials with 850 fill Downtek™ water-repellent down, for those who aren't willing to sacrifice comfort for compressibility 

Pad Cinch System is adjustable to a variety of pad sizes. The self-equalizing drawstring easily connects bag to pad and the middle securement feature provides extra stability 

Maximum thermal efficiency is achieved when inner and outer bags are layered, using offset quilted construction to minimize cold spots 

Sleep on any side using the inner bag alone and within the outer bag. Three-quarter, anti-snag, ambidextrous zipper stays out of the way when side sleeping 

The inner bag design mimics our award-winning Sidewinder sleeping bag, designed for side sleepers and made to move with you from side to side 

Keep your head snug and warm using the inner bag with jacket-style hood 

Spacious, rectangular shaped outer bag is constructed with no-draft collar, no-draft wedge, and a single no-draft, anti-snag left side zipper with zipper garage 

Ultimate comfort and additional hand warmth with hand tuck pockets at the top of outer bag 

Access from top and bottom of both inner and outer bag with two-way zipper for easy temperature control throughout the night 

Easy access to discreet pillow barn on pad sleeve, keeps your pillow tucked in all night 

Regular and Long sized bags available 

Storage sack & stuff sack included

Construction + Materials

Shell: Ultralight nylon rip-stop 

Lining: Ultralight nylon rip-stop fabric

Pad sleeve: Ultralight nylon rip-stop 

850 fill DownTek™ repels water while maintaining insulating value - bluesign® Certified PFC-free water-repellent chemistry 

Quilted construction

Here’s what other people think.

What’s in a Name?

Lost Ranger Peak, a few miles south of Big Agnes Mountain, is perched above one of the most beautiful basins in Colorado. In the dead of winter, it could possibly be one of the most inhospitable spots anywhere. Legend holds that rangers from North Park and Hahn Peak arranged a meeting on the peak and one fellow never showed thanks to a late September snow storm. It a topic of debate as to which ranger lost his way, the answer you get depends on which local ranger station you ask.