Size is 15 x 32, (15 inches neck and 32 inches sleeve). I'd say a SMALL.

Lightweight cotton tan US Army jacket with Sergeants stripes and Tropic Lightning patch of 25th Infantry Division, Oahu, Hawaii. Perhaps Khaki, hard to get color accurate in photos. It does have a greenish tint in certain light.

Very good condition. See photo for some staining near collar.

Let me know if any questions. Thanks!