Lighter and warmer
British brand Rab's Mythic Ultra series has created a completely new and innovative method to reduce the weight of sleeping bags to the maximum possible level while retaining warmth. A pioneering product that could be a game changer for runners and high-end alpinists.
I feel like I need more time to get back to my daily life and be in harmony with nature. I want to quickly pack my bags and enjoy camping in my free time. With the addition of new options, it has become an indispensable tool for minimalist auto camping during the harsh winter months. Also, I would like to summarize this product again because it is a reliable product that can be used in preparation for emergencies and disasters.
Specifications for the harsh space environment
Many of you may have seen the metallic film-like blankets used in times of disaster or distress. These are called emergency blankets, all-weather blankets, space blankets, etc., and are sheets that reduce heat loss from the human body due to heat radiation, water evaporation, convection, etc. Because they are lightweight and compact, they are easy to stockpile for disaster use, and they also have the advantage of being used as distress signals by reflecting sunlight, making them popular.
This thin, light, and heat-retaining technology was developed by NASA in 1964 during the Apollo program. In space, the parts of the body that are exposed to the sun become extremely hot, and the parts that are not exposed to the sun become extremely cold. This technology is used to prevent internal electronic equipment from malfunctioning due to strong temperature changes and to ensure stable operation, and consists of multiple layers of ultra-thin plastic sheets layered with metal reflective material. The technology developed to function in this extreme environment has been applied to the private sector and is now used as space blankets to protect us in emergencies and disasters. 
Inside Rab's "Mythic Ultra" series, a technology that uses radiant heat called TILT (Thermo Ionic Lining Technology), which is basically the same principle, is applied to the sleeping bag itself for the first time in the world.
What differs from blankets is that instead of layering film-like metal, the fibers themselves are coated with titanium, allowing the radiant heat of the human body to be reflected back into the bag without compromising the breathability of the fabric. In addition, it is an epoch-making mechanism that allows you to reduce the amount of down needed to obtain the heat retention necessary for the target temperature range. The outer material is made of supple 7-denier ultra-light ripstop material, and when you look at the actual product (Mythic Ultra 360), it is incredibly light at 606g, which is hard to believe for a winter product with a -8°C limit. This is a warm-to-weight ratio between the temperature range and the sleeping bag's "weight" that is far from common sense. 
A well-honed product
Rab values not only numbers and specifications, but also on-site testing, and has an outstanding environmental stance. In addition to the world's first heat-reflective lining technology, the down is a fluorine-free, water-repellent down developed in collaboration with NIKWAX with 900+ fill power, and is enclosed in a trapezoidal box structure with no cold spots. In terms of sustainability, we also use traceable down that is RDS (Responsible Down Standard) certified.
We have actually tested it in a variety of environments, and even when camping in the snow, it shows incredible heat retention for such a compact size. Also, when you hear titanium coating, you may imagine a metal-like texture that is unpleasant to the touch, but in reality it has a supple and smooth feel. There is nothing unpleasant about it when it comes into direct contact with the skin. I can feel Rab's attitude towards creating "usable tools" that are not just cosmetics. 
Optional systemization
Rob / Mythic G Down Jacket
The newly developed down jacket is Mythic Ultla 180/360 (800+ fill power) or more warmth, This is an ultra-lightweight high-end down jacket. Achieves warmth of 1000+ fill power in a light weight of 277g. The pack size is also very compact at 20 x 14cm. Maximizes the radiant heat of TILT. It is very useful as it can be used as an outer layer during the harsh winter months, and can be used with a sleeping bag while sleeping.
Rab / Hooded VB Liner
A sleeping bag liner made of extremely thin and strong silnylon. In fact, it is a niche product that is not even listed in catalogs and is only available in a limited number of stores around the world. This liner is used to prevent condensation inside the sleeping bag during the harsh winter months, but it retains more heat than you might imagine. In the warm season, I also use it alone as a sleeping bag. As it is light at 285g and has a pack size of 8 x 18cm, Nowadays, it is a must-have item that you always bring with you.
Wanderout / Insulation Sheet 00
Similarly, the 3D AERO LAYER developed by NASA was used as a spec for the harsh space environment. The blanket is excellent. Using aerogel, which was previously used as insulation material in spacesuits, is fixed to fibers using a 3D printer, and it exhibits incredible insulation properties considering its thinness of 250g. Airgel is the lightest material on earth and has the lowest thermal conductivity.Over 90% of its constituent material is air, making it extremely lightweight and insulating from high and low temperatures. The outer material is made of high-strength, lightweight 20D nylon that emphasizes weight reduction and packability, and is extremely soft and delicate to the touch. This is a very versatile insulation sheet that can be used all season as a blanket or sheet, wrapped around the neck, or placed inside a sleeping bag.
Rab/Down Hut Slipper
The sufficient warmth of 700 fill power will soothe your tired body from the bottom up. The elasticated collar keeps out cold air, while the brushed fleece lining and cushioned insole provide ultimate comfort. The outer material is made of water-repellent 30D Pertex® Quantum, and the sole is made of flexible and grippy nylon, making it tough enough to walk around the campsite. Lightweight at 198g and highly portable, these relaxing shoes can be used for a variety of purposes, not only for winter camping, but also in the car while traveling, at home, or at work.
Anyway, it is wonderful both technically and as a product, but if you are looking for a sleeping bag that you can simply sleep warmly in extremely cold environments for auto camping in the middle of winter, I recommend that you buy it in exchange for increased weight and large volume. , there are also many more affordable options.
However, to eyes accustomed to the primary-colored sleeping bags of red and yellow that are everywhere, and the no-longer-rare "fashionable" sand beige and olive drab colors, this solid black and metallic silver product seems like a "play". He may be seen as a highly honed, solitary being who does not tolerate "looseness." I am overcome with the urge to try my hand at this one-of-a-kind product, which has an atmosphere that goes beyond the realm of outdoor gear.
Perhaps this is because, deep within this thin, jet-black film, ``humankind's spirit of exploration into the unknown'', which ventures into the ultimate outdoor environment of space, is contained.
Rab/Mythic Ultra 180
Weight: 400g
Pack size: 32 x 16cm
Compatible temperature: Rab Sleep Limit 0°C (32°F)
Rab/Mythic Ultra 360
Weight: 606g
Pack size: 36 x 18cm
Compatible temperature: Rab Sleep Limit -8°C (20°F)
Rab / Mythic G Down Jacket
Weight: 277g
Pack size: 20 x 14cm
Rab / Hooded VB Liner
Weight: 285g
Pack size: 18 x 8cm
Wanderout / Insulation Sheet 00
Weight: 250g
Pack size: 25 x 11cm
Rab/Down Hut Slipper
Weight: 198g