The sizes are based more on US customers, although the company is from UK. The incision is very ergonomic, and luckily there are no widely protruding cuffs with thumb slot, you hardly need anyway. A few nice touches like the white embroidery on the collar and the logo on the shoulder highlight this fleece. My has greatly gefusselt when new on the inside, which went away only with the first wash. To this end, a star trigger - otherwise a real bargain!