The XS shirts fit perfectly. They are breathable and stylish. DHaRCO is my new favorite MTB clothing brand.
Good fit no rubbing or chaffing on long rides, I'm 5'11 100kg and purchased XL, I swing between L and XL sizes (L Patagonia, XL Fox, XL ASICS) great autumn shirt for Perth. .....even better it was on sale
This shirt looks and feels great, it means I can get sweaty and still feel good about seeing people I know. The material is super nice and light aswell.