Feathered Friends

Lark UL 10 Sleeping Bag

Lark UL 10 Sleeping Bag - Main image
$517.57 $729 In stock

Category: Three Season Bags

New for Winter 2025/2026: Our Lark 10 UL gets all-new Pertex® Quantum Pro® shell fabric + Pertex® Diamond Fuse lining fabric in the footbox, plus new and familiar colors

We made a favorite even warmer. The Lark is a rock-solid three-season sleeping bag built for comfort and performance when the nights turn cold. With a full down collar, additional fill, and premium 950+ fill power down, it delivers exceptional warmth while still packing down surprisingly small. A great choice for those who sleep on the cold side or venture deep into the shoulder seasons of spring and fall.

UL: Ultralight. Pertex® Quantum Pro® water-resistant/breathable fabric with 950+ Fill Power Down

Details

  • Mummy shape (average width) with #5 YKK two-way, separating zipper with locking sliders
  • Full collar provides an effective seal of down around your neck to trap the heat
  • Trapezoidal footbox allows your feet to fall in a natural pose without compressing the sides
  • Pertex® Diamond Fuse 15 denier footbox lining that offers more abrasion protection for more nights at camp
  • Continuous baffles let you position the insulation where you need it
  • 3D contoured hood opens wide for warm nights and cinches tight when the temps start to drop
  • Generous draft tube prevents cold air from seeping past the zipper
  • Includes storage bag & stuff sack

Specs

Ideal Sleeper Height Reg 6' 0" / 183 cm 
Long 6' 6" / 198 cm
Dimensions 59" shoulder / 64" elbow / 55" hip / 42" footbox
Zipper Left Side, YKK #5
Shell Pertex® Quantum Pro® 7 denier + 30 denier ripstop weave

The durable water repellent (DWR) finish on our Swallow UL Sleeping Bags is made without intentionally added perfluorinated chemicals (PFCs/PFAS)
Lining Flyte 10 denier recycled nylon +  Pertex® Diamond Fuse 15 denier footbox
Fill Power 950+ Goose Down
Origin Made in Seattle, USA of imported materials
Temp Rating 10ºF / -12.2ºC
Fill Weight Reg 1 lb 4 oz / 568 g 
Long 1 lb 5.2 oz / 600 g
Average Weight Reg 1 lb 14.9 oz / 877 g 
Long 2 lb 0.6 oz / 924 g
Packed Size 11L
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United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

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Customer Reviews (5.0 / 5 · 5 reviews)

Harper W. ★★★★★

The new shell fabric feels noticeably tougher than my old bag, and that Diamond Fuse lining in the footbox kept my toes warm down to the low 40s. Stuffs down into the compression sack without a fight, too.

Ella ★★★★★

Took this out for a chilly autumn weekend and the new Pertex Quantum Pro shell handled damp ground and wind without any condensation issues inside. The extra warmth compared to my old three-season bag was noticeable, and the footbox lining feels really nice against cold toes.

Claire ★★★★★

I’ve been taking this bag on early spring trips and the Diamond Fuse lining in the footbox really makes a difference—my toes stay noticeably warmer without adding weight.