Classic brown T-shirt in quality weight pure cotton.  The deep V-neck is bound in self fabric which looks a bit like satin and so this top could be quite dressy with the right accessories.  Very slightly shaped.  It is a richer brown than it appears on my screen.
Vintage, worn once only.

Approximate measurements unstretched:
Across chest under arms 15.5"
Back length 21.5"
Outside sleeve 15"
Inside sleeve 11"