Men's Levi's western-style denim long sleeved shirt.  EUC. 
Unique look; possible sample.  
Looks to be a Medium.  Please check measurements.

Pearl button snaps, also on pockets and cuff.  Western detailed pockets and back.  Rounded bottom hem.

Measurements:

Pit to Pit - 21"
Shoulder - 19"
Sleeve Length - 24.5"
Length (at longest) - 29.5"