ExtremeLite30°F / -2°CWide mummy

MegaLite

Mummy (w/ top collar)

Weight, 6′0″
1 lb 8 oz680 g
Insulation
850+goose down
Shell
12D ripstop nylonExtremeLite
Length
Zipper

$630

Made to order
Find in a store

Not sure about length or fit? Try our sleeping bag selection guide.

How warm is it, really?

EN/ISO extreme
-8°F
EN/ISO limit
22°F
EN/ISO comfort
32°F
WM rating
30°F

Our rating usually falls between the EN/ISO “limit” and “comfort” figures, and assumes a well-insulated pad (about R 5.0 in the cold), dry base layers and socks. How we rate our bags.

MegaLite – Ultralight Wide Sleeping Bag

The MegaLite is an ultralight wide sleeping bag built for backpackers who need room to move without carrying extra weight. At just 1 lb 8 oz, it delivers exceptional comfort, warmth, and packability for three-season use.

This bag features a wider mummy cut, offering more shoulder and hip space than standard ultralight bags. It’s perfect for side sleepers, restless campers, or anyone who dislikes tight quarters in the backcountry.

The MegaLite uses 850+ fill power goose down for high-loft insulation that compresses easily and lofts quickly. Full baffle construction allows the down to fully expand, maximizing warmth in cool-to-cold conditions.

A full-length #5 YKK zipper adds versatile ventilation. You can unzip the bag completely on warm nights or zip up tight when temperatures drop. An insulated draft tube prevents cold spots and seals in body heat.

The 12-denier ripstop nylon shell is lightweight, breathable, and water-resistant. It helps regulate moisture while keeping your insulation dry in damp conditions.

Use the MegaLite for thru-hikes, fastpacks, or alpine loops where nighttime lows fall near freezing. It offers a perfect balance of weight, comfort, and reliability.

Whether you’re chasing miles or just want to sleep better outdoors, this bag delivers space without compromise. It packs small, weighs little, and performs where it counts.

Proudly made in the USA, the MegaLite is Western Mountaineering’s answer for backpackers who want ultralight performance and unmatched comfort in one high-performing bag.

Features

  • Filled with 850+ Fill Power ethically-sourced premium goose down
  • Continuous baffles allow you to shift down for more insulation in colder weather
  • Full-length #5 YKK zipper provides a smooth, easy unzipping experience while saving weight
  • Insulated Draft Tube blocks cold air and keeps the torso better insulated
  • Breathable 12 denier ripstop nylon outer shell makes bag ultralight yet durable
  • Top draft collar with adjustable draw closure saves weight while keeping cold air from entering the sleeping bag
  • Comes with ultralight stuff sack and breathable storage bag
  • 1 lb 8 oz. Total Weight

Specifications

Shape
Mummy (w/ top collar)
Temp Rating
30°F
Fill
850+ Power Goose Down
Color
Navy Blue/Black
Country of Origin
USA
Fabric
12D ripstop nylon
Loft
4" in
LengthInside Girthshoulder / hip / footFill WeightTotal WeightStuff Size
5'6"63"/56"/39"11 oz1 lb 7 oz6"x12" XXS
6'0"64"/56"/39"12 oz1 lb 8 oz7"x13" XS
6'6"65"/56"/39"13 oz1 lb 9 oz7"x13" XS

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