Kalchedon, Bithynia, AR trihemiobol. 1.05 g.

Shield.
K-A-L-X between the four spokes of a wheel. 

Sear SG 3737; RecGen 7; Paris 333; Waddington 262 (all: this coin). 

Courtesy of the Bibliotheque Nationale, Paris, gallica.bnf.fr.