Alexander, AE follis, Carthage mint, AD 308-311. 

Obv: IMP ALEXANDER PF AVG, laureate head right.
Rev: ROMAE AE-TERNAE, Emperor, helmeted and in military dress, 
standing front, looking left, holding Victory and sceptre.

Mintmark PK.

RIC VI Carthage 71; Sear 15086.
Rated R4.
With permission of Dane's bank, UBS, Sept. 2008
Estimate: CHF 3,000.