Sidney SL 25°

Women's Superlight down fill traditional mummy bags with the REM Pad Sleeve that transforms your bag into a Big Agnes System bag

DownTek™ Water Repellent Down Insulation

Down sleeping bag insulation has long been the favorite of backpackers, thru-hikers, and mountaineers due to its relative light weight and ability to pack down small. While down bags generally cost more and require more care to keep dry in humid conditions, the soft feel of down is unsurpassed and extremely popular.

Responsible Down Standard

We're committed to using sustainable products wherever and whenever possible, including the down we use for our sleeping bags and outerwear. We strongly believe in using only down that comes from ducks & geese that were treated ethically, so we, as a company,  have committed to the “Responsible Down Standard”. All of the down Big Agnes purchases for our products comes from an RDS Certified supplier.

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Specs + Sizing

Bag WeightPet: 2lb 1oz / 936g / Reg: 2lb 3oz / 992g
Fill WeightPet: 19oz / 539g / Reg: 21oz / 595g
Compressed Bag SizePet: 5.5in x 8in / 14 x 20cm / Reg: 6.5in x 8in / 17 x 20cm
Stuff Sack SizePet: 7.5in x 15in / 19 x 38cm / Reg: 7.5in x 15in / 19 x 38cm


A pioneer among women's bags, this is the first of its kind to offer customizable fit to prevent cold air spots

These fully insulted bags offer a Big Agnes System option by using the included REM Pad Sleeve™ to secure your bag to the pad

The REM Pad Sleeve™ also doubles as a storage sack

Contoured hood baffles cradle the head for a more comfortable fit

Oversized interior anti draft collar

Unique exterior cinch system allows for a customized fit maximizing warmth and mobility without sacrificing weight and trapping more heat closer to the body

Big Agnes custom print

Interior zippered stash pocket

DownTek™ water repellent down repels water while maintaining insulating value

Low profile cordlock lets you un-cinch the hood with one hand

Zipper Garage

Interior fabric loops for sleeping bag liners

Exterior loops for hang drying or storage

Mesh storage sack & nylon stuff sack

Mate together left and right zip bags within same bag series

Construction + Materials

Traditional mummy shape allows for light weight and increased thermal value

Superlight Nylon rip-stop shell fabric with high tear strength and a water repellent finish

Nylon Taffeta lining

Insotect Flow™ construction

650 fill power DownTek™ 

60"/152cm YKK #8 zipper - petite bags

70"/178cm YKK #8 zipper - regular bags

Vertically structured side walls integrating contoured flow baffles trap heat closer to the body

Vaulted foot box creates more wiggle room for your feet

Here’s what other people think.

What’s in a Name?

The town of Sidney, located eight miles south of Steamboat, was inhabited by settlers in the early 1880's, before Steamboat existed. Sidney boasted a post office, school, church, blacksmith shop, creamery, and boarding house. With the introduction of the railroad, Sidney became a major shipping hub for agricultural goods. Today, Sidney Peak Ranch is committed to preserving the land's natural character so it will remain for another 125 years to be enjoyed by future generations.