I'm 6 foot tall and 140 lbs. I purchased the size small Ascent Aero LS Jersey. This is a lightweight jersey, not a winter or fleeced material. I have other Pactimo jerseys in size medium so this one fits closer to the skin. Arms are a great length despite the small size. My normal dress sleeve is 33/34. A slightly shorter body, like many jerseys these days. This keeps it from sagging while carrying food and a phone. I have worn it with a merino base layer, and on another occasion with a Pactimo wind jacket. Both options really extend the temp range of the jersey. Great in the red color too!