Weight 2 lb 1 oz / 940 g
Fill Weight 1 lb 3 oz / 538 g
Temperature Rating 15 F / -9.4 C
EN Comfort 28.9 F / -1.7 C
EN Lower Limit 18 F / -7.8 C
EN Extreme -14.6 F / -25.9 C
Fill 850 Fill-Power Down
Shape Mummy
Max User Height 6 ft 0 in / 180 cm
Hip Girth 58 in / 147 cm
Foot Girth 38 in / 96 cm



I have primarily used this bag in northern summers,…

Rating: rated 4 of 5 stars
Design: left zip mummy

I have primarily used this bag in northern summers, as an all purpose bag. I have spent two summers of trip leading sleeping it it all summer in Maine and Wisconsin/Minnesota, while also pushed its limits in October in northern MN and January in the Grand Canyon. I recently got a Sea to Sumit 8L dry sack for it, which it fits in perfectly. These bags are not submersible, and take the place of the garbage-bag-in-a-stuff-sack combo in my pack.

The only time I've ever felt the cold in this bag was through my ground pad when I needed something more than a short 3-season Therm-a-rest. My last night in the Grand Canyon I slept out under the stars and had ice form on the top of my bag and didn't know it until I crawled out in the morning.

Most recently I stuffed this bag inside my zero degree bag and slept out in -15 degree weather and stayed warm.


I was so excited about my Marmot Helium, the weight,…

Rating: rated 1 of 5 stars
Price Paid: $360

I was so excited about my Marmot Helium, the weight, the fit, and the size of it. It worked well for me on the first few trips out and nearly for the first year. I began to notice that some feathers were coming out, although I couldn't find a hole. I called customer service, and they weren't much help. Told me to wash it and how, which I did, following their directions.

I took the bag on a trip in the Wind River range, into some 15 to 20 degree temps and spent all seven nights miserable due to the cold. I called again and sent it back to them, along with the money they required to wash it and add new down. After several weeks with no bag, I received it with two ounces of down added. So I was ready to go again...I thought.

On the next trip in February in West Virginia, I was warmer, but I woke to a bag soaked with water. My husband was dry in his bag beside me. I called Marmot again, and they told me to treat it with Grangers.

What good is their warranty? Useless for me. Waste of my money. I will be looking for a better bag and a better product than this.

rated 4.00 of 5 stars All Helium versions

In addition to the 2 women's reviews above, there are 18 reviews for other versions of the Helium. Read all reviews »

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