Rab Mythic G Jacket Review: The ultimate ultra-lightweight down jacket that breaks the limits of "lightness and warmth"

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An ultra-lightweight down jacket that delivers exceptional warmth without sacrificing weight

When it comes to cold weather clothing to take with you on extreme cold outdoor adventures such as mountain climbing or backcountry skiing, the first thing that comes to mind is, as it always has been, a down jacket. The high insulating properties of waterfowl feathers that keep out the bitter cold and their compactness when compressed make them unmatched by any other material, even in this age of technological advancement

Among these mountaineering down jackets, the Rab Mythic Rab that prides itself on being a "master of insulation" after years of research and development into down and other insulation products since its founding . This time, we'll be reviewing this ultra-lightweight technical down jacket.

Key Features of the Rab Mythic G Jacket

The Rab Mythic G Jacket is an ultralight down jacket that delivers incredible insulation-per-weight performance. Its eco-conscious, premium 1000FP RDS-certified European goose down is sandwiched between an ultralight, PFC-free, DWR-treated 7-denier Atmos™ nylon ripstop outer fabric and our proprietary TILT (Thermo-Ion Lining Technology) lining, delivering maximum warmth with minimal weight. The carefully engineered draping creates a stylish silhouette, comfortable fit, and freedom of movement. Every element has been thoroughly redesigned and stripped down to the bare essentials, while retaining essential functionality like draft-tight hem and cuffs, a comfortable, warm hood, and handwarmer pockets for a snug fit.

Favorite points

• Ultra-lightweight and compact
• TILT (Thermo-Ion Lining Technology) provides the highest level of insulation per weight
• Outstanding three-dimensional cutting that combines "ease of movement, comfort, and a good silhouette" that only Rab can offer
• Highly designed hand pockets with concealed zippers

Points of concern

• (If I had to pick one thing) The delicate fabric and limited storage space due to the minimal amount of material used

Main specifications and evaluation

Detailed Review

the Rab Mythic G Jacket ? For me, this is an easy question to answer after using it in the field. For me, the appeal of this down jacket can be simply summed up in two points. One is that it is overwhelmingly " light and warm comfortable to wear in the field . Let me explain each point in order.

Insulation and weight: Provides sufficient warmth with weight reduced to the utmost, down to the gram

Why the Mythic G Jacket so much lighter and warmer than other down jackets? There are certainly many ingenious ideas that have been put into the details, but above all, there are two major points that should never be overlooked.

First and foremost is the quality of the down (feathers) stuffed inside. This jacket (men's size M) is filled with a generous 127g of 1000FP (fill power) European goose down, which is essentially the highest level of resilience (loft) available today. Therefore, it goes without saying that this jacket alone is a highly functional down jacket that is fluffy and warm when worn and extremely compact when folded

1000FP down provides extremely high heat retention even with a small amount of cotton

Of course, there are other manufacturers who offer jackets that use 1000FP down as the padding. A typical example is Montbell's "Plasma 1000 Alpine Down Parka." However, the Mythic G Jacket stands out from the rest in terms of "lightness and insulation" thanks to another innovation: a unique "insulation boost function." This is another key feature: the shiny "TILT (Thermal Ion Lining Technology)" lining that can be seen on the inside of the jacket (see photo below).

Tilt fabric lining covers the entire surface except for the underarm area

For details on how it works, please refer to the video on their official channel here (it explains the fabric, but the content is about sleeping bags). To put it simply, a special technique is used to coat each fiber with titanium, allowing radiant heat to be reflected inside the garment without impairing the breathability of the fabric. According to Rab, this effect significantly reduces radiant heat loss by up to 30% compared to when nothing is present. Incidentally, this is not the same as the "aluminum vapor deposition" used in cheap winter jackets (which are heavy and stuffy, so frankly, I wouldn't use them in the mountains)

This technology increases insulation without impacting weight, bulk or breathability, allowing for maximum warmth with minimal weight

As soon as you put it on, you'll feel so much warmth inside the garment that you'll wonder if the heat is coming from the jacket itself, and it's quite an impressive sensation, considering that this happens while wearing just a light jacket, so light you won't even notice you're wearing it

When I felt chilly on the ridge, I took it out of the compression bag and put it on, and it immediately provided excellent insulation

What I personally find clever is that while this TILT fabric is used for most of the lining, including the hood, the TILT fabric is deliberately removed from the underarm area. Furthermore, the down baffle has a "stitch-through construction" (stitching through the front and back), which deliberately reduces thermal efficiency and allows weak heat to escape through the seams. In other words, the basic concept is to maximize lightness and warmth, while also allowing heat to "escape" from unnecessary areas such as the underarms, so that it can be used comfortably as a "tool" for use in the field. These subtle adjustments would not be noticed without careful testing in the field. This is the work of someone who really "knows" what they're doing

Comfort and fit: The perfect fit and ease of movement mean you hardly feel any stress while on the move, which is nothing short of amazing

I'm 176cm tall and weigh 64kg and wear a size M. The fit is just right, with a little room to spare. If you don't want to wear it over a shell and just want a lighter layer, a size S would probably be fine

While many down jackets are designed for everyday wear and have a loose, cylindrical silhouette, this jacket has a slim fit that follows the lines of the body and a slightly longer length. The hem is longer at the back than at the front, providing ample coverage for the buttocks

Although it's slim, it's not restrictive. The three-dimensional cut that doesn't restrict upper body movement is as excellent as ever, allowing you to move your arms freely and the hem hardly ever rides up even when you raise your hands (see photo below)

The excellent three-dimensional cutting means that the hem hardly rides up even when you raise your arms high

By the way, regarding the optimal size, when I chose the M size, I was able to wear it over a base layer or mid layer, and there was plenty of room to wear it over a shell. If you want a tighter fit with less space between your skin, you can also choose the S size

The cuffs are partially made of elastic material, and the instep is slightly stretched, providing a comfortable feel and just enough tightness to keep out drafts

The cuff design is excellent as it keeps out the cold while providing a gentle feel against the skin

And as you'd expect from a lightweight jacket, the hood is quite simple. It's not adjustable, but there's a bit of stretch on the edges to improve the fit, and the top has a hard brim to help withstand wind. It doesn't appear to be designed to be worn over a helmet (though you can wear one in an emergency), but it fits snugly over a knit cap. The collar is high, and the brushed inner chin guard is a nice touch

The hood is warm and has a good fit thanks to the ample down content

Durability/Weather Resistance: Provides adequate protection considering its light weight, but is not overly durable

The jacket's shell fabric, both inside and out, is made of ultra-thin 7-denier ripstop nylon, woven at a high density to prevent down loss. While it's certainly a material that combines ultra-lightweight and durability at an extremely high level, it's also true that it can't be used roughly in the same way as a jacket of a normal weight. While I haven't had any particular issues using it so far, you should still handle it carefully to avoid rubbing it against rough rocks or trees, or getting it caught on sharp objects

This jacket also offers protection from wind and rain, and its PFC-free DWR treatment can even block light rain. Unfortunately, however, it's not a water-repellent down jacket, so you'll need to be careful when it gets wet

The DWR treatment on the surface repels water to a certain extent (it is not waterproof)

Functionality and usability: Minimal functionality with minimal waste

The Rab team's goal was to create an ultra-compact kit with maximum warmth-to-weight ratio for people moving at high speeds in extreme cold environments, so they stripped away everything that wasn't essential, and frankly, you can't expect much in terms of functionality

However, it does have the bare minimum of two large zippered hand pockets, a durable and freeze-resistant YKK Vislon zipper, and a drawcord to keep the hem snug, which, while minimal, are well thought out and don't feel particularly lacking in any significant way

Discreet hand pockets with concealed zippers

That said, personally, I still want a chest pocket. I don't usually put anything in the left and right pockets because they're uncomfortable and interfere with the waist belt, so I still need a chest pocket to store something. It may be unnecessary for extreme activities, but for a casual outdoor enthusiast like me, I'm willing to put up with the extra 10 or so grams, so please include a chest pocket

This is the size when stored in the stuff sack. It becomes quite compact, but in my case, I store it by tucking it into the gap in my backpack instead of putting it in the stuff sack because it makes packing easier

Summary: This is the best portable winter garment available today, condensing all the good things about down jackets. Once you wear it, you won't want to let it go, whether you're in the mountains or in town

The Mythic G Jacket has been refined to a new level, taking the three original advantages of a down jacket - lightness, warmth, and comfort - and is undoubtedly one of the best pieces of portable cold weather gear available today, perfect for alpinists taking on demanding missions or minimalists who prioritize weight reduction and want to keep in their backpacks in the winter mountains.

On the other hand, in terms of functionality and convenience, it is extremely simple (for the price), so it may not be suitable for everyone, and may not be cost-effective for people who want not only lightness, warmth, and comfort, but also safety and convenience

For me, the Mountain Hardwear Ghost Whisperer UL has long been my go-to lightweight down jacket. While it's certainly lighter, after discovering this jacket, I plan to switch to this one, which offers significantly better insulation and comfort. While it's a staple in my backpack in the mountains as a cold weather jacket, I've been wearing it every day for the past month as my favorite outerwear for outdoor activities down below

It certainly has its quirks, but if you can understand those quirks and find their simplicity appealing, then this is a supreme piece that will likely last you at least 10 years or more

   

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