Magma 850
Best lightweight insulation for backpackers seeking premium warmth on a budget.
This sleeping bag balances warmth and weight, making it an ideal choice for three-season backpacking. It features high-quality down insulation and a durable, breathable shell that manages moisture effectively. The design includes a fitted hood, a draft collar, and a smooth, anti-snag zipper system to ensure comfort and ease of use. While it offers a snug, efficient fit for back sleepers, it prioritizes thermal efficiency over spaciousness, making it a reliable companion for those who value performance and packability on the trail.
$399.00
Owner Satisfaction
4.6
/ 5
Category Rank
306
/ 2020
#306 in Sleeping Bags
Price vs Category Average
+139%
Above average
Who it's for
- Backpackers seeking maximum warmth for minimal weight
- Explorers who refuse to compromise on technical specifications
- Campers prioritizing ethical manufacturing and sustainable outdoor gear
Who should skip it
- Individuals who prefer a more relaxed, spacious fit
- Users easily frustrated by small mechanical gear failures
- Adventurers who frequently encounter abrasive or rocky environments
Performance breakdown
Warmth-to-weight ratio
High-loft down provides exceptional insulation without adding bulk to your pack.
Packability
Compresses down to the size of a loaf of bread effortlessly.
Draft management
Contoured hood and draft collar seal out cold air effectively.
Interior comfort
Spacious cut allows for natural movement without sacrificing thermal efficiency.
Moisture resistance
Treated down maintains loft better than untreated fill in damp conditions.
Zipper performance
Anti-snag design works smoothly even when you are half-asleep.
Know before you buy
The Magma 850 is typically rated for 15°F (-9°C), making it a solid choice for three-season backpacking and early shoulder-season trips. Keep in mind that this rating assumes you are using a sleeping pad with an appropriate R-value to insulate you from the cold ground.
The down is treated with a water-repellent finish, which helps it resist moisture and maintain loft better than untreated down. However, it is still natural down, so it will lose insulation if it gets soaked; you should always use a waterproof stuff sack or pack liner to keep it dry.
The bag features a semi-rectangular shape that offers more room in the hips and knees than a traditional mummy bag, which is generally more comfortable for side sleepers. If you tend to toss and turn, you will likely find the extra width in the torso and footbox helpful.
Yes, it includes a lightweight compression sack that allows you to pack the bag down to a very small size for your pack. It also comes with a larger storage sack, which you should use for long-term storage at home to preserve the down's loft.
The Magma 850 is designed as a standalone mummy bag and does not feature a zipper configuration intended for joining two bags together. If you are looking for a sleep system for two, you would be better served by a dedicated double sleeping bag or a quilt system.
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