Not sure what it is, but looks like spackle to me. Not sure of the size. I wear a large T shirt (175lbs and 6 foot tall). I can put the jacket on but its a bit snug.I would say its a Medium. Overall its in great shape for its age. Please review photos to evaluate the condition for yourself. Please let me know if you have any further questions or need additional photos. The item "US WWII, Korean War, Private Purchase Tankers Jacket -Great Shape" is in sale since Thursday, September 20, 2018. This item is in the category "Collectibles\Militaria\WW II (1939-45)\Original Period Items\United States\Uniforms". The seller is "forfun07077" and is located in Olathe, Kansas. This item can be shipped to United States.