Very cool 70s short sleeve shirt button down shirt by Etienne Aigner with the signature A on the pocket. Made from a cotton and polyester blend in Hong Kong. It says 16 which is the neck width and an overall size large.

Great looking shirt and in good vintage condition overall, one small stain on the front below a button (see photo) may come out with careful spot cleaning just using clarified water.

I believe this is a size Large to extra-large and has a little stretch. See measurements below with shirt laid flat for most accurate sizing. I suggest comparing these measurements to another shirt you like the fit of.

neck: 16"
shoulder to shoulder: 18"
armpit to armpit: 22"
waist; 19.5"
length: 30"

This item is sold from a vintage boutique in Pendleton, South Carolina.