The Alpinist. Center Zip Mummy Bag in 35° or 20°

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The Alpinist is Nunatak's ultralight mummy sleeping bag.

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With the Alpinist we sought to rework the traditional mummy into a sleeping bag we feel is more useful.

We moved the zipper from the side to a center front location. This gives you full use of both arms while still having head and back snug in the sleeping bag, a must when performing sitting camp tasks in less than ideal conditions.

This unique center zip provides more effective torso ventilation, but can also seal up very effectively via the double draft tube backing.

When side sleeping the zipper typically ends up slightly in front, down from the shoulder a bit. Whether it is open for venting or snugged up, this is an ideal location. From here the zipper is conveniently controlled without contortions, and the dreaded back side cold spot from traditional zipper placement on the side hem, is completely eliminated. In fact, side sleeping is almost where the center zip placement is at its best.

Remaking the traditional head opening into the Alpinist/Raku style hood is the natural follow-up to the zipper relocation and is very effective at keeping you warm with less material. When using the Alpinist in warmer conditions, pulling out the head and shoulders from the hood and lying on top is simple. It is easy to do a non-shifting pillow arrangement inside the hood.

The 20° Alpinist is built with a 2" differential cut, a feature that greatly increases the efficiency of a given fill volume.

A Multitude of Stock Options

The Nunatak Alpinist is likely one of the more customizable mummy bags on the market. Using the many options in the configuration menu below, one can create the perfect fit either for body size, special applications or desires. 


We offer 4 overall lengths, from small to extra long. 

3 different shoulder width options with corresponding increases in interior volume. The size choices carry on into the hood and hip area: for example an extra wide bag will also have a bigger hood and a roomier lower middle section. The standard 30" width is well sized for most individuals. If your desire is an extra roomy feel, choose 35", and for the very few needing the outmost in sprawl there's a 40" option. Be aware that a large interior volume requires a more energy to keep warm. 

The footbox circumference can also be individually sized, independent of length and width. Here the standard is the 38" circumference. For folks with small feet a 34" footbox will be warmer, and, off course, the big guys might consider the 42".

If your needs are not met by the easily configured options presented in the menu below, we also have unlimited custom adjustments available. Please call or email.

Shell Material

For the Alpinist we have literally a staggering amount of shell fabric choices. Please consult the Fabric Info page for detailed description. Basically there's 3 distinct groups:

*The UL (UltraLight) shells in 0.66 and 0.8 ounces per square yard.

*The standard shells in 1.0 oz/yd, plus a couple of nice camo fabrics and the venerable Epic.

*The two advanced waterproof/breathable options, one a super light 0.74oz/yd, the other a membrane laminate similar to Goretex, at 1.4 oz/yd . Take note that a significant increase in final cost is associated with these.

Temperature Rating35° or 20°
Baffle height1.25 or 2.25
Insulation Loft1.5 or 2.5
Fits to Height Small: 5' 4"....Medium: 5' 10"....Long: 6' 3" ....XLong: 6' 8"
Shoulder width options30" - 35" - 40"
Foot Area Circumference34" - 38" - 42"
Differentially cut liner/shell20° - 2"
Zipper28", 38" or 48" YKK Coil.
Fill Volume, 20°F, Long x 30" W x 38" Foot18,3 oz
Fill Volume, 20°F, Long x 35" W x 38" Foot20.3 oz
Fill Volume, 20°F, Long x 40" W x 38" Foot23.8 oz
35°F, Long - 30" W - Total Weight, 0.66 Membrane Shell/Liner21.5 oz
35°F, Long - 35" W - Total Weight, 0.66 Membrane Shell/Liner23.2 oz
35°F, Long - 40" W - Total Weight, 0.66 Membrane Shell/Liner25.6 oz
20°F, Long - 30" W - Total Weight, 0.66 Membrane Shell/Liner26.8 oz
20°F, Long - 35" W - Total Weight, 0.66 Membrane Shell/Liner29.9 oz
20°F, Long - 40" W - Total Weight, 0.66 Membrane Shell/Liner33.5 oz

Alpinist & Skaha sweater

Thank you for both the down sweater and sleeping bag. I recently returned from 8 days in The Tasmanian Wilderness and was absolutely satisfied with both products. The other three on the trip were very jealous of my sweater. We all needed to carry light gear because there were no food or fuel drops. All the others left their down jackets behind because they were too heavy. Not mine. So light. So warm. I love it . Also very impressed with down quality in the sleeping bag. The first few nights were warm and with previous sleeping bags I would have been perspiring and sticky but I layed it over me with zipper open and it was perfect. The last four nights the weather turned with a cold front and I snuggled in fully zipped up. Perfect. I think your down quality must be really good because in the past I have always had to wrestle with too hot or too cold all through the night. I had the best sleeps thank you. I am ordering a down sweater for my husband so I will be asking questions over next 2 days about the order before you are out of contact. Thank you again.

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    The Alpinist. Center Zip Mummy Bag in 35° or 20°

    The Alpinist. Center Zip Mummy Bag in 35° or 20°

    The Alpinist is Nunatak's ultralight mummy sleeping bag.

    Product Options
    Temperature Rating
    The 20° is a solid 3 season sleeping bag.
    Shoulder Width
    The standard works for most.
    Zipper Length
    38" and 48" zippers are YKK #5 two-way inside/out coil.
    The 28" option is an ultralight one way #3 coil.
    Foot Box Circumference
    Shell Fabric

    Please go to the Fabric Page for help choosing the shell material.

    Liner Fabric
    Down Type
    Choosing Hyper-Dry moisture resistant down will help combat the effects of perspiration, misting tents and damp air. Nunatak products made with Hyper-Dry down will have a slight increase in bulk over those made with regular down. In some instances they may contain an additional 5% of fill weight.
    Down Overfill
    Cold sleeper? Consider adding a few ounces of extra fluff.