This is a handsome Vintage Parker 51 Black Fountain Pen with Sterling Silver Cap. Marked around the cap it says "Sterling Silver", and "Made in USA". We know very little about pens, but this pen appears to be in very good condition. With some very small blemishes, and some tiny dings on the clip. 5 1/2 long with cap on.
The plunger seems to work ok, but we didn't try and fill the pen, so don't know if it actually. If you have any interest, please feel free to make an offer.. Thanks very much for looking!