Men's summer shirt by Marc O'Polo.  Pure cotton shirt with a loose weave like cheesecloth, and multi-coloured stripes.
Quite a large collar, with rounded tips, 1970s-style.  Buttons at the top - but not all the way down; you put it on over your head like a polo shirt.  Single cuffs with button fastening.

Size M
Actual garment measurements:
Chest 40" (maximum).
Shoulder to shoulder 16".
Length at the back 28".
Sleeve, shoulder to cuff 26".
Sleeve, armpit to cuff 21.5".

Condition:  Good quality shirt, in good clean condition.  Previous owner's laundry tag inside the neck.  This shirt has no holes, tears etc, and has just been laundered.