FlyLite – Ultralight Summer Sleeping Bag

The FlyLite is our lightest sleeping bag ever—a purpose-built ultralight summer sleeping bag for thru-hikers, fastpackers, and minimalist adventurers shaving every possible ounce. Weighing just 14.3 ounces, it’s designed for moving fast and far when conditions are warm and you want the lowest possible pack weight.

This half-zip mummy-style bag uses 10D nylon ExtremeLite™ shell fabric and 850+ fill power goose down to deliver maximum loft with minimal bulk. Rated to 36°F, it excels on true summer missions—low-to-moderate elevation trails, desert nights, and any trip where weight savings are the priority and insulation needs are intentionally modest (not a cold-weather solution).

The narrow cut and half-length zipper trim grams everywhere, while the insulated draft tube helps seal in warmth on cooler evenings. Despite its stripped-down build, the FlyLite upholds the Western Mountaineering standard for craftsmanship, durability, and long-term loft—ready for hundreds of trail nights.

For colder snaps, pair it with a hooded layer or insulated jacket; the FlyLite is light by design, not overbuilt. It compresses to the size of a water bottle and disappears into the smallest packs, making it a favorite for fastpacking and bikepacking where pack volume is at a premium and temps stay mild.

If you’re the backpacker who trims toothbrushes and counts every gram, this is your bag. When conditions are right, the FlyLite lets you push big miles, keep your kit ultracompact, and sleep comfortably—with fewer ounces on your back.

Features

Explanation

Filled with 850+ Fill Power ethically-sourced premium goose down Continuous baffles allow you to shift down for more insulation in colder weather Half-length #3 YKK coil zipper keeps bag ultralight while providing a smooth unzipping experience Insulated Draft Tube blocks cold air and keeps the torso better insulated Micro-baffled construction eliminates cold spots while making bag extremely packable Breathable 10 denier nylon taffeta outer shell makes bag ultralight yet durable Comes with ultralight stuff sack and breathable mesh storage bag 14 oz. Total Weight

Specifications

• US
• Metric

Shape	Mummy
Temp Rating	36°F
Fill	850+ Power Goose Down
Color	Orange/Grey
Country of Origin	USA
Fabric	10d nylon (248x248) balanced interlace weave
Loft	3.75" in
Inside Girth shdr/hip/foot	5'6" 59"/51"/39" 6'0" 59"/51"/39" 6'6" 60"/52"/39"
Fill Weight	5'6" 7.15 oz 6'0" 7.65 oz 6'6" 8.15 oz
Total Weight	5'6" 13.5 oz 6'0" 14.25 oz 6'6" 15 oz
Stuff Size	5'6" 5"x10" XXXXS 6'0" 5"x10" XXXXS 6'6" 5"x10" XXXXS

Shape	Mummy
Temp Rating	2°C
Fill	850+ Power Goose Down
Color	Orange/Grey
Country of Origin	USA
Fabric	10d nylon (248x248) balanced interlace weave
Loft	9.5 cm
Inside Girth shdr/hip/foot	165cm 150/130/99 cm 180cm 150/130/99 cm 200cm 152/132/99 cm
Fill Weight	165cm 202 g 180cm 217 g 200cm 231 g
Total Weight	165cm 383 g 180cm 404 g 200cm 418 g
Stuff Size	165cm 13x25 cm XXXXS 180cm 13x25 cm XXXXS 200cm 13x25 cm XXXXS