Airflow Button-Up Camp Shirt

I read the reviews before ordering hoping that since some said it ran small and others said it ran large, it would be somewhere in the middle. I wear a medium/large in tops. I went with a large because I wanted it to be loose fitting. It is too small. Most large tops are loose on me, but this one was really small compared to other large tops that I wear. I am returning and may get an extra large because I like the material, but fear it could gap around the armpits.