Here I have a pre owned Patagonia Ventura CA. T Shirt,  Size XL Slim Fit in Gray.  The T Shirt is in excellent condition,  no stains,  rips or holes,  not faded.   I will ship it with USPS.

Armpit to Armpit is 22 inches,  sleeves are 8 inches and the length is 30 inches.  More like a large to me.