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Nunatak Arc UL 30 — Specs & Analysis
Manufacturer specifications, compared against every other sleep systems in our database. We do not test gear in the field — we measure, verify, and compare.
A premium custom-made quilt from one of the most respected cottage manufacturers in the industry. The Arc UL 30 features 900-fill-power down and fully customizable dimensions for a perfect fit.
The Nunatak Arc UL 30 is what you get when a small-batch manufacturer obsesses over every detail of quilt design. Made to order in the United States with 900-fill-power goose down, each quilt is built to the customer's exact specifications — length, width, footbox style, shell color, and even differential cut proportions.
The level of customization is unmatched in the quilt market. You can specify your body dimensions to get a quilt that fits you perfectly, eliminating the cold spots that come with generic sizing. The differential cut — where the inner shell is cut smaller than the outer — maximizes loft where it matters and prevents down shifting.
Build quality is meticulous. The 10D Membrane shell fabric is whisper-light and nearly silent when you move. Baffles are precisely sewn to control down placement, and the stitching is cleaner than what you will find on any mass-produced sleeping bag. The 900FP down lofts beautifully and compresses to a remarkably small volume.
At 470 grams for a 30-degree quilt, the Arc UL pushes the boundaries of what is possible in terms of warmth-to-weight ratio. It packs down to the size of a small cantaloupe, leaving plenty of room in your bags for other gear. For bikepackers who count every gram, this kind of performance is transformative.
The trade-offs are price and availability. At 445 dollars with potential wait times of several weeks, the Arc UL requires patience and investment. The ultralight 10D fabric also demands careful handling — keep it away from Velcro and sharp objects.
For the bikepacker who wants the absolute best quilt money can buy and is willing to wait for a custom build, the Nunatak Arc UL 30 is the pinnacle of the craft.
Who Is the Nunatak Arc UL 30 Best For?
Experienced bikepackers who want the lightest, best-fitting custom quilt available. If that describes your riding style, the Arc UL 30 should be at the top of your shortlist. It sits in the Sleep Systems category alongside 19 other products we track.
How It Compares
At 470g and $445, the Arc UL 30 is 220g heavier than the lightest option in this category (the Therm-a-Rest NeoAir UberLite at 250g). The most budget-friendly option is the Cascade Designs Therm-a-Rest Z Lite Sol at $50.
The price-to-weight ratio comes in at $95 per 100g — a premium price point, but you're paying for quality, materials, and design that justify the investment for serious bikepackers.
What We Like
- +Fully custom dimensions for a perfect fit
- +Premium 900FP down with exceptional warmth-to-weight
- +Meticulous small-batch build quality
- +Incredibly compact packed size
Watch Out For
- −Premium price for a quilt
- −Long lead times for custom orders
- −Ultralight 10D fabric requires careful handling
The Bottom Line
We haven't scored the Nunatak Arc UL 30, and neither has anyone else we can cite. It's here for its verified specifications and dimensions, which is what the fit tools run on — a score is an editorial judgement, and we don't hand one out until someone has a basis for it. What this page can tell you is measured: 470g, $445, and how both sit against every other sleep systems product we track.
The price and weight above have not yet been checked against the manufacturer's own page. We are working through the catalogue and saying so as we go, rather than letting silence imply otherwise.
Specifications and dimensions come from the sources listed above. Where a page draws on first-hand riding, it says so.
What it packs down to
Nunatak publishes a packed size of 20 x 15 cm, which is 3.5 litres as a stuff sack. Of the 55 bags we track that publish a capacity, 37 have room for it and 18 do not.
Volume is computed from Nunatak's own packed size, treating a two-dimension figure as a stuff sack. Bag capacities are the makers' published figures, not ours — 12 of the bags we hold dimensions for publish no capacity and are left out of the count rather than assumed. A stuff sack does not reshape itself, so read the headroom as room to spare rather than a guarantee it goes in easily.
How it compares
Against the 20 sleep systems we hold published specs for.
At 470g the Arc UL 30 is lighter than 8 of 19 alternatives we track. The category median is 465g.
At $445 it undercuts 0 of 19 of them, against a median of $235. That works out at $95 per 100g — above the $53 median for sleep systems.
Weight and price come from published specifications. Cost per 100g is a blunt measure — it rewards light gear and says nothing about durability or whether the thing works — so treat it as one input, not a verdict.
More in Sleep Systems
Sleeping bags, quilts, and pads that pack small and keep you warm on the trail.