This is a gorgeous shirt from Johnnie-O.

Made of lightweight cotton, it's a plaid in a soft sage green.

The shirt has a button-down collar with hidden tabs, a left chest pocket, and a squarish tail.

This shirt is in PRISTINE, MINT condition.  Looks and feels unworn. It is guaranteed to be authentic and absolutely perfect. 

I have measured the shirt and: 

The neck measures 15.5 inches from button to button hole.

 The sleeve length is 34/35 inches from mid-collar to the end of the cuff. 

Across the back, laid flat, the shirt measures 22 inches armpit to armpit and 31 inches from the collar seam to the bottom of the back tail.