Marmot Helium EQ 15 Degree Sleeping Bag

What is back is: High end for of Spring, Fall, and not extremely cold Winters. Best used for mountaineering or long backpacking trips in cool weather.
The most impressive feature is the stuff/compression and expansion size. It fits into a XS Marmot stuff sack, which his 14x7 inches. Think of an Xbox 360 smushed into a cylinder. You look at the stuff sack and say ‘There is no way it will fit into that’ but it does. The down is comfortable and expands to the fullest. The weight is one of the lightest on the market. I weighed it on a food scale and in the stuff sack; it weighed 2 lbs 8oz. It is very warm as well. There is an inner flap behind the zipper so no heat can escape of cold air let in. I used the bag, under the stars in late spring. The weather for the night ranged low 50s to high 30s F. The bag was so hot I woke up and had to unzip it all the way and use it as blanket until 3:00am or so.
What this bag is not: Not used for Car camping, Summer time, novice users (Boy Scouts/Summer Camp)
It is not a summer bag. Any temperature above 40 degrees F the bag is pretty much useless, as it is too hot. This is not a roomy or comfortable spacing bag. To cut down on the weight Marmot cut down on the size. You cannot lift one knee. It is very snug and mildly cramped, based on my size. I am 5'11 160lbs with broader shoulders. I used the Regular version.
Two other features to note; the zipper does take a few moments to get use to. The inner flap does catch in the zipper if you do not run your finger ahead of the zipper when opening/closing. Also getting out of the bag is not a straight shot. It does take some finesse and slight patience.
However if you want a bag with the smallest stuff size, with the lightest weight while not too concerned about sleeping room, then this is your bag.

Having only had a cheap pathetic bag in the past, a comparison would be foolish. I was so pleased that we could afford to buy good bags; I had high hopes that it would be money well spent. I have not been disappointed, these bags are excellent. We just used them on a trip to Anza Borrego, where the night time temps were in the 50s but with the full length zipper, it was easy to ventilate the bag to avoid being too warm. If you're looking for a great three season bag, this is it.

Comfy, warm, and light weight. The Marmot Helium EQ 15 degree down sleeping bag was perfect for my camping trip to a local lake. Although it was 100 degrees during the day, I was stoked to have this bag for how warm but light weight it is. Doesn't take up a lot of space but the only reason I didn't give it 5 stars was because I felt like it was a little difficult to put back in it's carrier. What a small price to pay for such a nice bag...I'm very happy with it!

I got the long bag and it fit me well at 6'1" 195 lbs. I slept in 20 deg F, and was warm and comfortable. The water resistant coating (EQ) cuts the wind and the rain. It only came in a left zip, which is less convenient for my right zip bivies. This great 15 degree bag only weighs 2-1/2 lbs. The Marmot stuff sack is no good. The sack ripped by the entrance on the first trip. Get a good quality small compression sack to go with this super bag.

but otherwise it's absolutely wonderful. I got this bag because I was taking a trip to Australia. In a swag in the middle of the outback in the Australia fall I had to unzip this bag all the way because it was so warm, same situation on a sheep farm with night temps in the 30s. I keep it in an event small stuff sack when traveling and in the provided laundry looking bag while at home.

This bag is super light and really warm. I've yet to use it on any really cold nights (like below 30 degrees) but so far I haven't had any issues. I'm 5'8" and I have an XS and it has plenty of room. The stuff sack it comes with is pretty tight and every time I think there's no way it's going to all fit in there but it always does.

After having my last marmot bag for over 12 years, it finally needed to be replaced. The Marmot Helium EQ is warmer, lighter, more durable, and compacts much smaller than any other bag I compared. With constant trips in the San Juans, as well as being a Wilderness First Responder, this is the ultimate bag for any situation. Believe me, it is well worth the price!