Antoninus Pius AE22 of Kyzikos, AD 138-161. 4.6 g. 

AY KAI T AI ADRI ANTWNEINOC, bare head right.
KYZIKHNWN, coiled serpent with head right. 

Hunter 30; SNG Hunterian 1206; Consul Weber 2417; BMC 1919-4-17-127.