When I bought this I used it for the first time on an Ultra challenge, it didn’t rain but as it started to get cooler it was a fantastic wind breaker and also kept me warmer than I thought it would without getting sweaty! I bought a size small, I’m around 5’8” chest size approx 36-38” and usually hover between small and medium. I went for small and I’m glad I did as it’s still baggier on me than expected but nothing too drastic, definitely a looser fit though to fit layers underneath if required.
I’ve also used this when it absolutely chucked it down (thunderstorm rain) and really wasn’t expecting it to keep me dry as I don’t understand what the technical numbers mean in the description of ‘waterproofness’. I had a tshirt on underneath so I could feel the material on my arms and thought I was going to be soaked when I took it off. Much to my delight I kept absolutely bone dry and no shoulder wetness at all it was fantastic!!! Very lightweight too!
Buy it, it’s the usual decent quality you’d expect from these guys :) thank you!