First test: Rab Mythic Ultra 360 sleeping bag review

Rab seeks to do away with compromise with its Mythic Ultra 360 sleeping bag. We have a look to see if they've succeeded.

Rab Mythic Ultra 360 sleeping bag being used in snow

by Ben Weeks |
Updated on

Rab's award-winning Mythic Ultra sleeping bags are coated with titanium to reflect the user's heat back into the bag. But is it a gimmick or a game-changer?

There is always compromise in outdoor gear. If it’s lightweight, it probably won’t be feature-rich; if it’s tough enough to stand up to the worst winters, it’ll be back-achingly heavy; and if it’s super-durable, it might be super-uncomfortable too. But when it comes to sleeping bags, perhaps compromise is a thing of the past, thanks to Rab’s new Mythic Ultra sleeping bags...

The Derbyshire-based brand has seemingly achieved the impossible: boosting the warmth of its bags by a third without adding weight. This apparent miracle is achieved thanks to a technological breakthrough. Rab’s Thermo Ionic Lining Technology (TILT) coats the sleeping bag’s fibres with titanium, thus reflecting the user’s heat back into the bag and enhancing thermo-efficiency.

It looks like the bag’s silver inner has a reflective, foil-like liner, but the tech here is far more scientific. We don’t really understand the chemistry, but the titanium is woven in at fibre level using a vacuum, ions and other complicated boffinry. The result is a warmth-to-weight ratio so impressive that the Mythic Ultra 360 picked up ‘Product of the Year’ (top prize) at the UK Outdoor Industry Awards 2020.

Just so you know, while we may receive a commission or other compensation from the links on this page, we never allow this to influence product selections.

Rab Mythic Ultra 360
Price: $525.00
Alternative retailers
Backcountry$487.50View offer

6 things you need to know about the Rab Mythic Ultra 360


Ethical down: Using only RDS-certified, ethically-sourced goose down, this bag is filled with an impressive 360g of 900+ fill power hydrophobic down. And, due to the heat-reflective technology, less down than normal is needed for a given level of warmth.

Trapezoidal baffles: It isn’t just TILT tech making this bag warm: the angles of the bag’s baffles, known as ‘trapezoidal boxwall construction’, improves the evenness of down distribution and reduces its movement, thus eliminating cold spots.

Temperature ratings: The temperature ratings, tested to new European standards, are -2°C comfort, -8°C comfort limit and -27°C extreme: impressive indeed for a 3-season sleeping bag weighing in at just 606g.

Cosy collar and hood: The baffled internal collar is cosy and can be easily tightened using a handy tension cord. The adjustable hood is similarly comfy, but it’s quite small and minimalist rather than a full, wrap-around style to completely cover the head.

Half-length zip: You get a half-length main zip, which – while not the easiest for getting in and out of – does the job. An anti-snag zip guard and slightly luminescent puller are nice touches, and the left-only zip orientation should be fine for all but the fussiest of campers.

Storage: The Mythic Ultra sleeping bags are made from wafer-thin, ultralight nylon, so protecting them from rips and tears is essential. Rab provides a lightweight compression stuff sack for use out on the trail, while a cotton storage sack enables safe storage of the down bags at home.


Price £700 | Weight 606g **| Size (**length x shoulder x hip x foot) 215 x 70 x 52 x 41cm | Packed size 36 x 18cm | Temperature rating comfort limit -8°C | Insulation 360g of 900-fill hydrophobic goose down | Material 7D ripstop nylon | Sustainability RDS-certified down, Fair Wear, fluorocarbon-free down

Also in range Mythic Ultra 180, 400g, £550

Trail verdict:

Rab’s titanium thermal technology is a game-changer: incredible warmth-to-weight ratio is achieved through clever heat-reflective fibres, making this sleeping bag a must for ultralight enthusiasts.

Rab Mythic Ultra 360
Price: $525.00
Alternative retailers
Backcountry$487.50View offer

Rab Mythic Ultra 180
Price: $347.69
Alternative retailers
Backcountry$346.50View offer

Down sleeping bag care and cleaning

Like any product that uses a technical fabric and down insulation, sleeping bags needs to be cleaned and cared for in order to remain effective. Grangers and Nikwax both offer effective water-based, PFC-free down cleaners that clean sleeping bag fabric and revitalise its water repellency (if it has any) without damaging the down insulation (regular laundry detergent is not good for down).


Substitute for laundry detergent. Can be used in washing machines or for a hand wash.

Grangers Down Repel 300ml
Price: $12.87

Good for down or synthetic insulation. Revitalises water repellency and breathability. Can be used with Gore-Tex. Suitable for washing machines and hand washing.


Works in a similar way to Grangers products. Follow instructions for best treatment.

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