This item is a WW-II Signal Corps telegraph key with a most unusual design.
It has both binding posts directly attached to the key contacts as shown in the photo. The coin silver contacts are 3/16". This must have been for some special high-current carrying capacity application.
Signal Corps stamp still visible on the back (see photo).
Made out of cadmium-plated brass with a steel lever.
All parts present. Light rust on the steel lever. Plating excellent. Nicely oxidized patina.
Handles fine in use.
$30 + postage. Shipping cost is $2.58 via first class mail. No expense to the buyer for materials or packaging. Buyer can pay by personal check if desired.