What Our Gearhead® Experts Are Saying:

"I'm a side sleeper, and this is hands-down the most comfortable bag I've used. The body-mapped insulation makes a huge difference at the hips and knees, and I love how the bag moves with me when I roll over. The 20°F rating is perfect for spring and fall trips."

We’ve tossed and turned our way through plenty of mummy bags, but the Sidewinder 20°F Sleeping Bag finally gives side sleepers a reason to sleep well in the backcountry. Designed for the natural way most of us sleep, it features a sculpted shape that moves with us as we roll from side to side, plus extra room at the elbows and knees where we need it most. Whether we're curling up on a cool fall night or shifting positions mid-sleep, this bag keeps the warmth close and the pressure points off.

Insulated with a hybrid of water-repellent 650-fill DownTek™ and body-mapped synthetic insulation, the Sidewinder 20°F targets warmth where we need it—around the hips, shoulders, and knees—while staying compressible enough to pack easily. The recycled polyester shell features a PFAS-free water-repellent treatment to block moisture and condensation, while the close-fitting jacket-style hood seals in heat without restricting movement. Lightweight, warm, and tuned for real comfort, it’s built for the way we actually sleep outdoors.

Similar Down Sleeping Bags

Down Sleeping Bags (139)

Synthetic Sleeping Bags (86)

Kids' Sleeping Bags (10)

Brand

Big Agnes (12)

Kelty (8)

Marmot (13)

Mountain Hardwear (15)

NEMO Equipment Inc. (12)

Rab (14)

Sea To Summit (17)

The North Face (10)

Therm-a-Rest (8)

Western Mountaineering (30)

Color

.css-2gcc7g{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#369;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}blue (44)

.css-1nhbdo3{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#093;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}green (23)

.css-1pgjne4{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#ccc;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}gray (21)

.css-1c4afls{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#f00;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}red (15)

.css-1ryiaxq{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#ff0;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}yellow (13)

.css-uc0kmc{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#f93;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}orange (11)

.css-yab3pc{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#000;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}black (6)

.css-2z3tn4{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#efb780;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}beige (3)

.css-7bc19j{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#963;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}brown (2)

.css-19q3wht{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#f39;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}pink (1)

.css-1ingyn9{height:23px;width:23px;border-radius:50%;margin-right:var(--chakra-space-1);background-color:#639;box-shadow:inset 0 0 0 3px #fff,0 0 0 1px #ccc;}purple (1)

Gender

unisex (126)

female (10)

male (3)

Sale

10% and more (139)

20% and more (94)

30% and more (94)

40% and more (14)

Features

Draft Collar (99)

Abrasion Resistant (67)

Hydrophobic Down (62)

Venting (44)

Pockets (31)

Pad Retainer (13)

Waterproof (9)

Price

$0 - $49.99 (6)

$100 - $199.99 (52)

$200 - $499.99 (46)

$500 - $999.99 (29)

$1000+ (6)

Recommended Use

Backpacking (115)

Weekend Camping (100)

Winter Camping (39)

Mountaineering (33)

Shop By

Gearhead Picks (8)

Shape

Mummy (119)

Semi-rectangular (18)

Rectangular (3)

Responsibility

Recycled/Repurposed (63)

Responsibly Sourced (63)

Bluesign Approved (13)

Temperature Rating

15º to 35º F (84)

-15º to 10º F (32)

< -20º F (14)

40º F + (10)

Customer Reviews

4 stars & Up (89)

3 stars & Up (94)

2 stars & Up (95)

1 star & Up (96)

Neutrino Sleeping Bag: 20F Down

Neutrino Sleeping Bag: 20F Down - Women's

Neutrino Sleeping Bag: 10F Down - Women's

Ascent Sleeping Bag: 20F Down

Cosmic 20 Sleeping Bag: 20F Down - Women's

blue (44)

green (23)

gray (21)

red (15)

yellow (13)

orange (11)

black (6)

beige (3)

brown (2)

pink (1)

purple (1)