1981 One Troy Ounce Silver Trade Unit One Ounce Silver Coin?

One ounce silver coin? - 1981 one troy ounce silver trade unit

I have a coin and want to know how much it is worth. Money is a part, "
An ounce
31.1 grams
Sterling Silver 999
Silver Trade Unit
"
This also has the image of a flying eagle with an American flag waving behind the eagle.

On the other hand, is as follows: "
U.S. silver coins strategic reserve
Once stored in the laboratory analysis of the U.S. --
San Francisco
CC
1981
"
This aspect has three stars on each side of the date of publication of this kind, "*** 1981 ***"

Please let me know what it's worth and where can I find more information about this piece.

Thank you!