This is a very good base layer shirt or a good training/running shirt on a cool day. It is very light and airy and is made of a new generation of moisture-wicking material. The fit is snug but not too tight. I think I will mainly use it as an undershirt in cool or cold weather. I generally prefer sleeves with straps that wrap a little tighter around my arm near the wrist than these, but I think they're tight enough to blend well with the outer layer. Look for the words "Mission" on the back. It's not a problem for me, but make sure it's ok for the intended use.