True vintage men's shawl sweater from Polo Ralph Lauren. 

Lying flat down approx. size measurements unstretched:
XL
Shoulder: 20 inches/50.8 cm.
Armpit to armpit: 22.5 inches/57.2 cm.
Sleeve: 28 inches/71 cm.
Back center length(bottom of collar to hem): 28.25 inches/71.5 cm.