1980s Vintage Demetre V Neck Wool Sweater Rainbow Early Yellow Ribbon Gay Pride M/L. Says Large but fits Large tightly. Probably more of a modern Medium. Has the yellow ribbon which was used for AIDS awareness prior to 1991 so this dates no later than that. See photos.

Pit to Pit: 21"
Shoulder to Bottom hem: 26"
Armpit to Sleeve hem: 18"