Caracalla, AE28, Serdica.

Obv: AVT K M AVP (VP ligate)/ANT-NINOC, laureate, draped, cuirassed bust right, seen from behind. 
Rev: HGE dot KAIKINA dot LAPGOV around, CEP/DWN within oak wreath. 

Ruzicka 101; Sofia 1677 

Courtesy of Nemesis Ancient Coins store on vcoins, Nov. 2010.