From the Herakles Numismatics vcoins.com store. See http://www.herakles-inc.com/

Bithynia, Prusias ad Hypium. Maximus - Son Of Maximinus I & Paulina. Hero Kieros. Countermark. 


Reign: Caesar, A.D. 235-238. 
Denomination: Æ 31 mm. 
Weight: 19.52 grams. 
Obverse: Bust r.; countermark (laureate, draped head r.). 
Reverse: Bust r. of hero Kieros (or founder). 
Reference: SNG Von Aulock 907. Ex Waddell Auction I, 12/9/82, 125. 
Grade: Good Very Fine. 

 Price  
  US$ 775.00   euro 510.09
 £ 390.47
 AUD$ 823.74
 CHF 808.50
 CAD$ 764.93
 
Rates for 3/3/2008