T Shirt Worcester MA 21st Annual Firefighters 6K No Tag Measures as Size S Small

T shirt, Worcester MA Firefighters 21st Annual 6K. Blue base tee shirt, with no tag. I would consider this a men's XS/S or a youth XL, but please note actual measurements and compare to a t shirt you own: Measuring laying flat. Armpit to armpit =17.5 inches. Back, measuring down center, not counting the collar band = 25 inches. Pre-owned item in good condition, light wear, no holes, no tears, no stains.