“I am 5' 8 or about 172 cm tall. I weight about 170 or 77kg. My chest is about 102cm and I bought the Large size. I have an athletic build and am carrying a few extra kg right now, and the fit is snug but also fits well. Super comfortable. The merino is soft on the skin and has great thermoregulating abilities both in warm and cooler temps. Nice styling. Great rear pockets that don't sag with a phone. I like the longer length of short sleeves. Well made and a quality product. If you sound about my size go for the Large.”