Vintage 
H BAR C 
California Ranchwear 
Long Tail Nevada 
100% Polyester Shirt 
Approximate dimensions:
armpit to armpit 20"
sleeve from collar to end 30"
collar to hem on back is 31"

I didn't want to remove the pins when taking pictures, I will
leave that to the lucky buyer! 
From what I see online, a size 15 and armpit to armpit measuring 20"
would point to this shirt being a mens size small.