Nick our Equipment Buyer gives this ultralight insulator from Rab a testing:

It is my pleasure this autumn/winter to be reviewing one of RAB’s lightest and most technical down jackets, the Mythic alpine Light. I have owned many down jackets over the last 20 years, and much like the favourite fleece, they are something that I wear on a daily basis throughout the year.

In my opinion, you can’t beat garments like these. They are so versatile in most conditions other than full on summer. The amount of warmth for the weight and the freedom of movement they give is unmatchable. Walking to work, sat in a chilly office, out on the moor for the day, even climbing an easy circuit of boulder problems or an easy route, it can all be done in lightweight down jackets like the mythic

So, what is different or new about the mythic alpine light than other down jackets I have owned in the past?

Well, the main difference or upgrade for me is that it utilises 900 fill power Hydrophobic down. This is really a very high fill power. My old jackets such as the Arcteryx Cerium and Mountain Hardwear ghost whisperer were both 800 Fill and the RAB microlite alpine was only 700 Fill, and none of those had a hydrophobic treatment.

The upshot of the higher fill power is that due to the better efficiency in trapping your warmth, the less of it you need (only 80 grams in a size medium). This directly translates to a smaller pack size and lighter weight for a jacket of the same comfort temperature. It is so light that leaving it lying around on the floor when climbing can even lead to it blowing away in breezy conditions!

So light it might blow away!

Comparing it to the ghost whisperer and the Cerium it is a slightly smaller pack size which is pretty handy when having it clipped to a harness. You would barely know it is there until you are nice and warm when stood on a belay ledge or sat at the top of the crag belaying your partner.

It can also be packed and carried around in pretty much any day bag with little or no space and weight penalty which is great as you get to use it so much more. My old favourite fleece, the Mountain Hardwear monkey man, is probably not quite as warm, is about 3 times the size packed and over twice the weight!

RAB have also used synthetic insulation, the best quality Primaloft gold version, in a few areas on the jacket. The cuffs, hood and the shoulders all benefit which is a good idea and similar to my old cerium jacket. I would have also liked to see the bottom hem baffles in synthetic and a fully synthetic hood and chin guard rather than the hybrid set up they have gone for. Whilst I wouldn’t go out of my way to wander around in the rain in the mythic, I would feel fairly confident it will survive a shower with no ill effects, plus it will layer perfectly well underneath a waterproof for the wet cold days out.

The features on the mythic are similar to most other lightweight down jackets in its category, a couple of zipped handwarmer pockets, adjustable hem, elasticated cuffs and a hood. The hood is non-adjustable but is a very good fit, much better than the ghost whisperer and even the cerium which does have a volume reducer but still manages to be baggier than the Mythic. It really pulls in well around your neck and helps stop the warm air escaping as you move around.

So how warm is it?

Well, I have rigorously scientifically tested it (ha-ha)

Basically, I stood outside in the garden at a windy 8 degrees Celsius for 5 minutes, then wore the other 3 garments mentioned above for the same time period and compared my feelings of warmth.

Outdoors I think the mythic does beat the other 2 down jackets, partially due to the great fit which is bound to help, and weirdly it felt a little more wind resistant as well. It beat the fleece hands down which is to be expected.

Having used it for afternoons walking out on the moors and coastal paths, and crag approaches with a pack on, I can safely say I have never felt cold when moving in it, but we are yet to have had any really cold weather to test it. (more pics for here to come I think)

Will it be durable ?

You will definitely have to look after a garment like this as it uses such a thin face fabric. The 10 dernier ripstop nylon is good quality but definitely not up to something like bushwhacking through brambles. My original ghost whisperer which has a 12 dernier face fabric is going on 10 years old and I still use it today. It has been stuffed in and out of a pack a lot and been worn on hundreds of easy boulder problems and yes there are small cuts in the face fabric, but they are easily repairable


Overall, I think it a definite upgrade on my previous jackets. The fit is very well tailored, the aesthetics are pleasing (love this marmalade colour) and the performance is on par or better than its nearest competitors, so I give it a thumbs up and look forward to using it more throughout the winter to come.