Here is a super cool short sleeve polo shirt by David Martin Menswear. 60% cotton, 40% poly. Dark blue fabric throughout. Four buttons at the collar, with a buttoned pocket on the left breast. Super soft and comfy. This one is in excellent condition with tons of life left! The tag says 2X Big, but here are the measurements. (refer to the last pic above to see how I measure shirts)

Chest (armpit to armpit) 25"
Shoulder to end of sleeve (including cuff) 10"
Length 31"

This item is sold from a vintage boutique in Roanoke, VA.