Corinth, AR Trihemiobol. 0.63 g. 

Corinthian helmet right.
Large T within incuse square. 

BCD Corinth 38 (this coin); SNG Copenhagen 21.

Very rare.

With permission of Numismatik Lanz, Auction 105, lot 38.

Ex Glendining & Co., Auktion 21. Juni 1972 (London), Nr. 220.