Features: It’s extremely lightweight – 140g (m), 142g (w) – and packable, coupled with a technical slim fit and a capacious adjustable hood that will fit over a helmet. There are three pockets and water-resistant zips throughout.  

Fit: It has an athletic cut. I’m of slim build, just below average height and a small fits me perfectly, with the arm length spot on. It’s the kind of jacket you put on and it feels as if there is no fabric going to waste. The hood is very generous, which is great for fitting over a bike or climbing helmet, but for people who won’t use it in those circumstances, it’s more than is needed. That said, it’s adjustable and the cord works well to take up the excess fabric. 

Comfort: Rain shells don’t get any more comfortable than this. The Pertex Shield fabric is thin and stretchy which, coupled with the efficient cut, makes it feel as if you’re wearing a very light windbreaker. Apart from the large hood, the only thing that bothered me were the cuffs, which are slightly loose, and cannot be tightened. Some Velcro here would help seal in warm air and keep water out. 

In use: I used this jacket on a rainy day trip with a moderate day pack and on a three-hour bike ride. When walking in light rain, with a Polartec Power Grid base layer underneath, the fabric stood up to its claim of extreme breathability. It also kept the water out, while the hood cinched firmly around my head. But in prolonged moderate rain, I discovered this jacket’s Achilles heel: the armpits have been perforated to improve breathability, but this also lets in rain and in this instance enough to leave me with two long saturated stripes down the front of my base layer. My pack straps may have enabled water to flow more closely to the armpits, but jacket design should allow pack use in mind. 

This flaw limits this jacket’s use to moderately bad weather and circumstances where you are not too far from shelter.

Value: It’s made from cutting edge fabric and is a mostly well-considered design, but I think the price is high for its limited versatility.

Verdict: I wanted to love the Bantamweight, and there is no doubt that it provides great protection from cold wind and light rain. It’s a perfect jacket to take on a multi-pitch climb when the weather is iffy and you know shelter is only a few hours away, or a fast and light day trip or bike ride when you’re returning to base. I’d like to see it without the perforated armpits to improve its range of use and reliance as a storm garment. 

Plusses: Super light, comfortable, very breathable. 
Minuses: Leaks in moderate to heavy rain, cuffs could be improved.