Lost Ranger 3N1 15F Down Sleeping Bag

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Versatile, spacious and well-designed for pad integration, this modular sleep system offers strong three-season performance with room to move.

Big Agnes says: 

The Lost Ranger 3N1 sleeping bag combines two sleeping bags for three different configurations – providing a sleep solution that’s just right at a wide range of temperatures.

This modular 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. Use just outer bag for warm summer nights, just the inner bag when temperatures start to drop, and on the coldest trips combine both for ultimate warmth – it’s the only bag you need for 3-season camping, backpacking and everywhere in between. These lightweight, down-fill bags deliver comfort and versatility no matter your sleep style or temperature preference.

Our Verdict

The Lost Ranger 3N1 15F features an inner and outer bag, allowing for three sleep configurations that adapt easily to changing conditions. At 1258g (Regular), it’s not the lightest setup available, but the flexibility and comfort make up for the added bulk. The semi-rectangular shape and Sidewinder-style inner bag give noticeably more space than a standard mummy, which is especially useful for side sleepers.
The Padlock system keeps the bag securely anchored to your mat, eliminating the issue of sliding off during the night. There’s no insulation on the base, so a properly rated pad is essential for use in colder conditions. The stated comfort limit of -9 °C is optimistic; actual comfort for most people will sit closer to -2 °C to 0 °C, depending on layering and mat choice.
The build quality is strong, with reliable stitching and a smooth fabric throughout. Features like the pillow barn and corner hand pockets add useful comfort without extra weight.
This is a well-executed modular bag for those prioritising adaptability, sleeping comfort and effective integration with a good pad.

– Reviewed by Ultralight Outdoor Gear

Features

• The 3N1 System offers multiple configurations for wider temperature versatility
• Modular down sleeping bag system includes a semi-rectangular outer bag and a Sidewinder- style inner bag designed to be used in combination or independently
• Outer bag features the Big Agnes PadlokTM Sleep System with Cinch Pad Sleeve
• Big Agnes PadlokTM Sleep System keeps your bag and pad connected so you can sleep comfortably without rolling off your pad
• Cinch Pad Sleeve adjusts to securely fit a variety of pad sizes
• When inner and outer bags are used together, offset quilt lines eliminate draft areas
• Use the top corner hand pockets to wrap the outer bag around shoulders like a comforter at home
• Insulated no-draft zipper tube
• Jacket-style hood on inner bag fits snugly for thermal efficiency
• Pillow Barn on pad sleeve allows natural head movement and keeps a pillow (or jacket) tucked in all night
• 2-way anti-snag zippers on outer bag for a smooth, quick zip and easy temperature regulation
• Storage sack & stuff sack included

Specifications

Temperature Rating

Comfort: -3°C (Combined) | 9°C (Inner Bag Only)
Comfort Limit: -9°C (Combined) | 5°C (Inner Bag Only)

Regular

• Combined Weight: 1258g
• Inner Bag Weight: 541g
• Outer Bag Weight: 717g
• Fits up to: 6’ / 183cm
• Fill Type: 650 Downtek™ PFC-Free
• Fill Weight Combined: 539g
• Fill Weight – Inner Bag: 283g
• Fill Weight – Outer Bag: 255g
• Pad Sleeve: Cinch Pad Sleeve 
• Compressed Size: 22 x 29cm
• Stuff Sack Size: 20 x 44
• Stuff Sack Volume: 14L 

Long

• Combined Weight: 1394g
• Inner Bag Weight: 607g
• Outer Bag Weight: 787g
• Fits up to: 6’6” / 198cm
• Fill Type: 650 Downtek™ PFC-Free
• Fill Weight Combined: 595g
• Fill Weight – Inner Bag: 312g
• Fill Weight – Outer Bag: 283g
• Pad Sleeve: Cinch Pad Sleeve 
• Compressed Size: 22 x 30cm
• Stuff Sack Size: 20 x 44
• Stuff Sack Volume: 14L 

Pad Size Needed

• Minimum: 20” x 72” / 51 x 183cm
• Maximum: 30”x 78”/ 76 x 198cm
• Rectangular shape recommended

Material & Construction

Fabric

• Shell & Pad Sleeve: Recycled 20D polyester ripstop PFAS-free water-repellent finish
• Outer bag lining and Inner bag: Recycled 20D polyester taffeta with PFAS-free water-repellent finish

Insulation/Construction

• 650 fill Downtek™ PFC-Free repels water while maintaining insulating value – bluesign® approved PFAS-free water-repellent chemistry
• 15°: Inner Bag, Quilt-through construction / Outer Bag, Quilt-through construction
• 0°: Inner Bag, Baffled construction / Outer Bag, Quilt-through construction
• Inner Bag: center-zip YKK #3 zipper
• Outer Bag: left-zip YKK #5 zipper

Sustainability Notes

• This product contains 100% Certified RDS Down Certified by Control Union CERT 879262
• Downtek™ PFC-Free uses bluesign® approved PFAS-free water-repellent chemistry
• PFAS-free WR finish on fabrics
• Recycled fabrics

Help & advice:

• The Ultimate Guide to Lightweight Sleeping Bags
• Time-Saver Guide to Choosing a Sleeping Bag
• About Rab
• Rab Mythic Sleeping Bag Range Explained
• Rab Sustainability and Responsibility
• Down Quality
• All About Down
• Hydrophobic Down
• Recycled Content in Outdoor Gear