Here is a super cool short sleeve polo shirt by Munsingwear. 65% poly and 35% cotton. Pretty in pink shirt with four button front, a button at the back of the collar, and the iconic penguin in white on the left breast. This one is in excellent condition with tons of life left! The tag says Large, but here are the measurements. (refer to the last pic above to see how I measure shirts)

Chest (armpit to armpit) 22"
Shoulder to end of sleeve (including cuff) 10"
Length 29"

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