What a great piece from year's back.
Glentex RN15542
Estate item, executor told me it is from the 60's.
Bolero type short jacket for a child.   Open front, no closure.  Long sleeved.  Fully lined.  Vintage label.
I do not know the size but it does have a M, measurements are 15" shoulder to shoulder, 19" armpit to armpit, and 15" length, 15" inner arm inseam.
There is some staining, soft of a gray look stain.  I have not tried to refresh or remove the stains.  This has been stored in a linen closet for years.
Very nice high quality construction.