If Active Insulation is space travel, then the Rab Alpha Direct is the first moon landing. There have been lots of good efforts in the field, but the Alpha Direct is undoubtedly new, exciting and unprecedented. The jacket is loaded with Polartec Alpha Direct insulation and Pertex’s Microlight face fabric, making it a powerhouse of high-tech fabrics. I’ve been thrashing an Alpha Direct for the last six weeks on snow, rock and ice and now it’s time to report the details.

Rab Alpha Direct Jacket Features:

• Built for spring-to-fall active alpine pursuits
• Light, water-resistant shell fabric
• Polartec Alpha Direct insulation allows unprecedented breathability
• Pertex Microlight fabric is durable yet light
• Under-hood helmet with tricot-lined collar
• Slim fit for comfortable layering
• Stretch fleece cuffs for uninhibited mobility
• Drawcord at hem seals out chilly gusts
• MSRP: $265

New heights for active insulation:

Even as I write this review, I have several other active insulator jackets hanging up in my closet waiting to be tested. The field is flooded with new offerings right now, so what, if anything, makes the Rab Alpha Direct stand out?

The most obvious feature is also the jacket’s most distinctive trait – the Polartec Alpha insulation is exposed on the inside of the jacket, giving it a furry look and a fleecy-soft feel. In most jacket, the active insulation is protected on the inside by a layer of nylon or polyester fabric, often mesh. That design protects the insulation while still allowing vapor to transmit easily through the jacket to the outside.

While that design certainly works, there’s no doubt that that protective lining does slow things down a bit. Rab was the first company that I’m aware of to remove that inner lining, exposing the insulation directly to your baselayers. Theoretically, this means that, although the insulation looses that protective layer, it can transmit heat much more efficiently.

So how does it work? Well, this will always be a little subjective, but in my testing it worked very well indeed. To start with, the feel of the jacket is incredibly soft and comfortable, and it’s surprisingly warm for its weight. The jacket feels like it ‘heats up’ more quickly than jackets with liners, perhaps because your baselayer is exposed directly to the insulation’s fluffy fibers. When things heat up and you start sweating into the jacket, the fibers do a remarkable job at transferring moisture and drying out. I normally get sweated-out forearms during heavy exertion but there has been none of this with the Alpha Direct.

That Polartec Alpha is bound to another important piece of technology, the Pertex Microlight fabric. Pertex’s Microlight is a soft, durable nylon fabric that’s hard-wearing and tear resistant, but soft and pliable enough to move well with the use. On the whole, the Alpha Direct has excellent range-of-motion, aided by Rab’s excellent alpine fit. The Alpha Direct features zoned fabric panels, so there’s different weights of the Microlight in critical areas like the shoulders and tops of sleeves. The Microlight is topped off with a great DWR.

The rest of the jacket is unassuming yet functional. We have a smooth-sliding main zip topped off with a zipper garage, two mesh-lined (read: good for venting) hand pockets and a Napolean pocket. All zippers slide smoothly and easily and I haven’t had trouble with snags. There’s a Velcro tab to tuck away the hood, which is a peculiarly English fascination – Rab is an English company and you almost never see this feature on US-designed jackets.

The hood design is good, with a lightweight wire brim and a microfiber peak that is comfortable under a helmet. The hood is designed to be worn under helmets, not over. There’s also Rab’s signature tall chin guard, with a wonderful fleece lining for cold chins. Finally, there’s also soft thumb holes in the sleeves to help with layering. I do notice quite a few loose threads around the cuffs, though. The hem drawcord works well to keep the jacket down under a harness, and the jacket climbs very well. I did a couple of ice pitches in it and the DWR was more than enough to fend off trickles.

Finally, for reference, I’m 5’11” 185lbs and tested a Large. It fit perfectly for alpine endeavours when a little extra protection is desired.

The Good

• Directly next-to-skin Polartec Alpha is an excellent performer
• Zoned Pertex Microlight fabric is strong and light
• All jacket features work well, including pockets and pullcords
• Chin guard design is especially good
• Fit is perfect

The Bad

• Only time will tell if the exposed insulation is durable
• Too many loose threads at sleeve cuffs for a jacket of this quality

The Bottom Line: Rab Alpha Direct

I compared this jacket to the moon landing in a slightly facetious way, but there’s no doubt that the Alpha Direct is the most important active insulator since the genre was created. Its design incorporates all of the features you need in the alpine, but ultimately the insulation is the jacket’s main claim to fame. It’s a great option for adventures of all sorts, and I’ve done everything from snowshoeing to ice climbing in it.

Buy Now: Available from Amazon.com