The signature shirt, with the sleeves left on
The same cut as the short sleeve signature: fitted through the chest and taken in at the waist, so it holds a shape instead of hanging off one.
The sleeve is cut to sit clean when it is down and stay put when it is rolled, which is most of the reason to own one.
Cooler evenings, and the office
Lightweight and breathable enough to keep wearing in the warm, with stretch through the body and a wrinkle resistant finish that means it comes out of a case ready.
If you are between sizes, size up. The stretch adapts either way.