Watch List notes:

ABBASID: al-Ma'mun, 810-833, AR dirham (2.99g), Wasit, AH200, A-223.4, Lowick-1485, citing al-Hasan below the obverse field, Dhu'l-Ri'asatayn below reverse (with the additional letter K below), very rare mint for al-Ma'mun, choice VF, RR.

Estimate: 300-400 USD