- Features
- Filled and Finished in Santa Rosa, California
- Certified 850+ Fill Power Goose Down - The Best Weight to Warmth Down in the Market; Independently Tested and Certified by International Down and Feather Laboratory in Salt Lake City, Utah. Retested at Fill Time in Santa Rosa to Ensure 850+ Fill Power Every Time. If the Down Does Not Meet Our In-House Test, We Send It Back
- EN Tested
- Pertex© Shield® Waterproof/ Breathable Shell
- Pertex© Microlight® Lining Fabric
- Passive Collar
- Classic Trapezoidal Foot Box - For More Foot Room
- Hood Draw Cord - Positioned for Easy Access
- Insulated Draft Tube - Eliminates Cold Leaks Through the Zipper
- Nautilus 6-Baffle Hood - 6 Chambers of Down Around Head for Better Down Control and Fit, Hood Cord is Positioned for Easy Access
- Stretch Tricot Baffles - Provide Ultimate Strength, Durability and Bag Life
- Stuff and Storage Sack Included - Store and Pack Just Like Your Sleeping Bag
- Velcro®-free Face Muff - Keeps the Drawcord and Zipper Away from Your Face
- Zipper Guards - Help Repel Biting Zipper Coils
- Zipper Garage
- Linked Styles
- Style Name:Helium MemBrain Long
- Style Number:20020
- Weight:2 lbs 9 oz / 1162 g
- Fill weight:21.5 oz / 610 g
- Price:$489.00
- Style Name:
- Specs
- Colors:
- Pacifica (025)
- Overall Weight:2 lbs 5.05 oz / 1050 g
- Fill Weight:19.5 oz / 553 g
- Size on Hip:58in/147.3cm
- Size on Foot:40in/101.6cm
- Main Material:MemBrain® 2L 100% Nylon Ripstop 2.3 oz/yd
- Lining Material:20 Denier 100% Recycled Polyester Mini Ripstop DWR 1.0 oz/yd
- Insulation Material:850+ Fill Power Goose Down
- Colors:

Marmot MemBrain®
MemBrain® fabric balances the best performance in waterproof, breathable fabric with excellent durability.
MemBrain® reduces internal condensation while increasing comfort by reducing the chilling effect caused by condensation build-up.
When used with insulated garments or sleeping bags, MemBrain® protects the insulation from harsh weather conditions.
850 Fill Down

Certified 850+ Fill Goose Down bags are constructed with the following features:
- Nautilus Hood: the same construction as our 8000m jacket hood, a 3D hood that wraps around your head and reduces heat loss.
- Hood Muff: creates a warm down gasket around your face, keeping the drawcord away from the face.
- Stretch Tricot Baffles: allow the bag to be stuffed and unstuffed without tearing the baffle material.
- Trapezoid Foot box: matches the shape of your feet, wider in the toe area and narrower in the heels.
- Down Fill Oversized Draft Tube: eliminates cold spots
- Zipper guard: keeps the draft tube fabric from getting caught in the zipper
- Ground Level Seams: top layer wraps fully around the body creating a warm layer of down.

Down
From the beginning, down has been Marmot’s foremost insulator. No synthetic surpasses the lightweight, compactability and longevity of down.

Marmot Down DNA:
Down is in our DNA. Marmot was founded in 1974 as a manufacturer and seller of premium quality down jackets, vests and sleeping bags. To this day we only use the finest quality certified goose down for our down insulated outdoor products. Mountaineers and outdoor enthusiasts worldwide rely on Marmot down gear for warmth, comfort, and sometimes survival.
Marmot Down Quality:
Down quality is determined by fill power and durability which is dependent upon the age/maturity of the bird and the processing of the down. The best down comes from larger, more mature birds and goose down is better than duck down (when age/maturity are equal). More mature goose down has larger filament clusters than less mature goose down. These clusters, when grouped, provide many more trapped air pockets and therefore provide better insulation. To maximize the effectiveness of the down clusters, the proper processing of the down (sorting, washing & drying) is required to open them up.
Higher fill power means higher loft, better insulation, lighter weight, and greater durability. We test all of our down for content, cleanliness, species, and fill power. We guarantee minimum fill power for all of our down clothing and sleeping bags. That means, for example, that our 800 fill sleeping bags are guaranteed to have at minimum 800 fill power. We don’t believe in + or – variation when it comes to comfort.
Down Origins:
Down is the light, fluffy undercoating at the base of the feathers of waterfowl. Down is a multi-dimensional structure that insulates by creating pockets of still air that retain body heat. Down is highly breathable and exceptionally comfortable. Pound for pound, high quality down is the most efficient natural insulator there is.
Geese are raised primarily for food and the down that is derived from them is a by-product of the food industry. Geese are raised on large and small farms and roam free outside on these farms. This is their natural environment. They are not raised indoors in controlled conditions. Geese are grain fed and also have access to local plant life.
Geese are generally harvested after 4-9 months for food. Some female geese are kept for breeding stock and are harvested between 1-2 years. These are the geese called the “mother birds” that provide the best, most mature down. After the geese have been harvested for food, the down and feathers are removed, washed, dried and then sorted by separating the down and small feathers from the larger, heavier feathers. These processing methods determine the final quality and fill power of the down. Marmot currently buys down primarily from Russia, Poland & China.
Marmot Guaranteed For Life:
Since 1974 we’ve guaranteed every product we’ve made for the life of the product. We believe the best thing for everyone and the environment is to make products that last.
Have a closer look - download the Marmot down desktop and keep your computer warm.

EN Tested
How do I read the EN information?
Basically the EN graphic shows a temperature range:
| Comfort Limit | The first number is based on a standard woman having a comfortable nights sleep |
| Lower Limit | The next number is based on a standard man at the lowest temp to have a comfortable nights sleep |
| Extreme Rating | The last number is a survival rating for a standard woman |
For example, the rating on our Pinnacle 15º Sleeping Bag shows:
| Comfort Limit | 22.2 degrees |
| Lower Limit | 10 degrees |
| Extreme Rating | Minus 24.7 degrees |
In this example, if a woman who sleeps cold is planning a trip with expected lows between 15 and 25 degrees, she could definitely use the Pinnacle 15 bag. But she may instead consider buying a zero degree bag to sleep more comfortably at the lower temperatures.
Testing Center
Marmot began as a sleeping bag company and we continue to pioneer performance, value and insulation standards in the outdoor industry. All Marmot sleeping bags are EN tested to ensure quality and performance. During the development process, we send all samples to the Thelma Testing Center in Norway. We continually use the Thelma Center to achieve continuity in our results.
What is the EN 13537 test? EN, short for European Norm, is a government test for sleeping bags.

How is the EN test conducted? First let’s be clear that it is challenging to test temp ratings because there are so many variables. Every person will sleep differently in the same bag. Choices like clothing, sleeping pad, tent or no tent, eating and drinking before bed can all affect one’s sleeping experience. For the EN test, a copper mannequin named Charlie is fitted with 20 sensors and a clothing layer (top, bottom, and socks) that provide a consistent thermal value. The mannequin is placed in the sleeping bag and put onto a wood platform roughly 12mm thick. The board is held above the floor with some support which allows air circulation under the board. The board is covered with a mattress that has a consistent thermal value then placed in a cold room. A mathematical formula is used to measure the data received from the sensors based on human modeling.
Why is there an EN Test hangtag on Marmot bags? Marmot sleeping bags sold in Europe require this testing and hangtag. We include this hangtag on all of our bags, as we believe it is the most reliable and accurate measure of the performance of a sleeping bag currently available.
How does EN testing differ from other methods and is it better? When Marmot first started testing bags, especially when we used Gore-Tex® fabric, our designers would go into meat lockers and sleep over night. Once they were able to sleep through the night they looked at the amount of fill to determine the temp range. Nowadays it is a bit more scientific. The testing method used in the US is very similar to the EN test. They use a copper mannequin, but the clothing, pad, and math formula are different. Again we feel the EN test is the most reliable and accurate measure of the performance of a sleeping bag currently available.
Has the feedback from the EN testing improved the designs of Marmot bags? Yes it has. The vast majority of our bags have tested to our current temp ratings. In some cases, the tests showed our bags were actually warmer than the rating we gave it. In another instance, there was a spot that showed room for improvement which led to more efficient baffle construction. With our baseline testing started in 2004, we can now measure improvement over time through new fabrics, insulation, and construction techniques.
Will the EN test become an industry wide standard? That is unknown. Currently our industry can’t agree on how the testing should be done because of all the variables. The European government has stepped in and taken control of standardized testing. For the meantime, Marmot will continue to test with the EN standard.
Marmot rating vs. EN rating?
Marmot’s assigned temperatures are comparable
to the EN lower limit rating.
During Marmot’s development process we send
all samples to the Thelma Testing Center in Norway.
Continually using the Thelma Center allows us to achieve continuity in our results.
Curly's Clips - Caring for Marmot Sleeping Bags
Marmot's own Curly Cervone and Brian Rashap demonstrate how to properly care for you Marmot sleeping bag.
Curly's Clips - EN Testing
Marmot's own Curly Cervone and Randy Verniers explain EN Testing on sleeping bags and how it can help you as you shop for the perfect bag in this edition of Curly's Clips.
Curly's Clips - Marmot Down
Marmot's own Curly Cervone and Randy Verniers explain why Marmot Down is the best on the market.
Size Chart
| 4'11"-5'2" | 5'2"-5'6" | 5'6"-5'10" | 5'10"-6'2" | 6'2"-6'6" | |
| 90-110 lbs | XS | S | |||
| 110-135 lbs | XS | S | M | ||
| 135-160 lbs | S-M | M | M-L | ||
| 160-195 lbs | M-L | L | L-XL | ||
| 195-230 lbs | L | L-XL | XL-XXL | ||
| 230-265 lbs | XL-XXL | XXL-XXXL |
Sizing by Body Measurements
| XS | S | M | L | XL | XXL | XXXL | |
| Parkas/Jackets/Sweaters/Tops (Unisex) | |||||||
| Chest | 33-35 | 36-38 | 39-41 | 42-45 | 46-49 | 50-53 | 54-57 |
| Neck | 13.5-14 | 14.5-15 | 15.5-16 | 16.5-17 | 17.5-18 | 18.5-19 | 19.5-20 |
| Sleeve | 30-31 | 32-33 | 34-35 | 35-36 | 36-37 | 37-38 | 37-38 |
| Pants/Bibs (Unisex) | |||||||
| Waist | 26-28 | 28-30 | 31-33 | 34-36 | 37-39 | 40-42 | 44 |
| Hip | 36-38 | 38-40 | 40-42 | 43-45 | 46-48 | 50-52 | 56 |
| Inseam (reg) | 28 | 29.5 | 31 | 32.5 | 33 | 33.5 | 34.5 |
| Inseam (short) | 26 | 27.5 | 29 | 30.5 | 31 | 31.5 | 32.5 |
| Inseam (long) | 30 | 31.5 | 33 | 34.5 | 35 | 35.5 | 36.5 |
| Gloves (Unisex) | |||||||
| Girth | 6.5-7 | 7-7.5 | 8-8.5 | 9-9.5 | 10-10.5 | ||
| Parkas/Jackets/Sweaters/Tops (Women's) | |||||||
| Size | 4-6 | 6-8 | 8-10 | 12-14 | 14-16 | ||
| Bust | 30-32 | 32-34 | 35-37 | 38-40 | 41-43 | ||
| Sleeve | 29-30 | 30-31 | 32-33 | 34-35 | 36-37 | ||
| Pants/Bibs (Women's) | |||||||
| Size | 4-6 | 6-8 | 8-10 | 12-14 | 14-16 | ||
| Waist | 22-24 | 24-26 | 27-29 | 30-32 | 33-35 | ||
| Hip | 33-35 | 35-37 | 38-40 | 41-43 | 44-46 | ||
| Inseam (reg) | 27.5 | 28.5 | 30 | 31.5 | 32 | ||
| Inseam (short) | 25.5 | 26.5 | 28 | 29.5 | 30 | ||
| Inseam (long) | 29.5 | 30.5 | 32 | 33.5 | 34 | ||
| Gloves (Women's) | |||||||
| Girth | 6-6.5 | 6.5-7 | 7.5-8 | 8.5-9 | |||
Kid's Sizing (boys & girls)
| XS | S | M | L | XL | |
| Age | 4-5 | 6-7 | 8-9 | 10-12 | 13-15 |
| Chest | 24-26 | 26-28 | 28-30 | 30-32 | 32-34 |
| Waist | 19-21 | 21-23 | 23-25 | 25-27 | 27-29 |
| Hip | 24-26 | 26-28 | 28-30 | 30-32 | 32-34 |
| Inseam | 17-18 | 19-20 | 21-22 | 23-25 | 26-28 |
| Sleeve | 22-24 | 24-25 | 25-26 | 26-28 | 28-30 |
| Height (in.) | 36-42 | 42-48 | 48-54 | 54-60 | 60-65 |
| Weight (lbs.) | 35-42 | 42-50 | 50-60 | 70-90 | 90-115 |
Garment Sizing Information
The charts above will help you select the proper size.
If you have questions, please call us.
Care Instructions
Marmot does not recommend dry cleaning for any of our products. Gore-Tex® fabric products, MemBrain® fabric products, down insulated products, and fleece are all machine washable. You should use a commercial front loading machine and follow the care instructions.









Reviews and comments
on 4/27/10.
Love it. Ultralight + Ultradry = one happy hiker.
I never have to explode my pack to dry my bag at mid day rests and can still cowboy camp with impunity. I woke up one day to find my z-lite full of tiny puddles, and just had to wipe the bag off before stowing it. I'll never have to smell wet down again. I'll definitely get another when this one wears out in twenty or so years.
on 5/26/10.
Is there any difference between Helium MemBrain and former Helium EQ? Why was the name changed?
on 5/27/10.
Hi Yury, thanks for your comment. The name was changed because the fabric comes from a different manufacturer. Both are waterproof and breathable.
Thanks,
on 5/31/10.
Sorry for my bad English.
Please, can I to shop model "Helium MemBraine" for woman?
I whant to shop 2 sleeping bag:
- Helium MemBrain Reg RightZip
- Helium MemBrain LeftZip for my wife (special woman's model 175cm size, but if it is found to be impossible, - reg).
on 5/28/12.
The Long is 7" x 14" inside the included XS stuff sack.
on 6/7/10.
hey, what's the stuff size on this bag?
on 6/22/10.
I just noticed that you changed the helium EQ to Helium membrane. Is there a difference in the way the interior of the bag feels. I have an EQ and it always feels a bit strange almost sticky inside the bag. How's that for a technical term. It just doesn’t have that normal sleeping bag feeling. Other than that NO complaints. Great bag warmer than exspected.
on 6/24/10.
My third Marmot bag. Extremely lightweight for the loft and warmth. The waterproof fabric keeps you dry in all conditions. Toasty in below zero conditions if you're a warm sleeper. Thanks for another great product, Marmot! My 23 year old, -20 degree Gortex Gopher is still going strong!
on 7/15/10.
Want to join 2 Helium EQ (MB) together, right and left zip to make one for couple sleeping together. Can do with Helium??
on 7/16/10.
Yes, the RZ and LZ will zip together to make one larger bag.
on 8/25/10.
Fantastic bag, kept my toasty warm up in the Yorkshire Dales in the middle of winter, nice comfy night and shrugged off the morning dew!
Too hot for summer hiking, but when my RAB Quantum 250 dies i 'll def look into the lighter Atom
on 10/18/11.
I actually use mine (Helium EQ) for summertime mountain and shoulder season desert backpacking all the time. Except in the coldest conditions, I just lay my bag over me like a blanket. When it is warmer, I don't pull it up as far and natural night time twisting a turning seems to let in the right amount of drafts to adjust the temperature under the bag. In cold weather, I'm sure I must still toss and turn but I must grab a tighter hold on the bag to avoid cold drafts. Not sure if this will work for you but I often sleep very comfortably with the down blanket approach while others with much less insulated synthetic bags complain about hot and stuffy bags in the morning. Of course if you have an even lighter bag, use it.
on 2/6/11.
Can some one tell me what is the difference of compressed sizes between the helium MemBrain and the standard helium in its respectives stuff sacks?
on 3/14/12.
What is the shoulder girth of the Helium bag?
on 6/4/12.
62in, 157.5cm
on 4/18/12.
I'm interested in buying one of these bags. I'm concerned it will be a big small for me...can you tell me size of the bag at the chest?
Also, what is the packed size of the bag?
Thanks
on 6/4/12.
The size of the bag at the shoulders is 62in, or 157.5cm. the pack size is 7x14in, or 17.8x35.6cm.
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