Watch List notes:

Diadumenian. As Caesar, AD 217-218. AR Denarius (19mm, 3.50 g, 6h). Rome mint. 2nd emission, 2nd phase of Macrinus, early AD 218. Bareheaded, draped, and cuirassed bust right / Diadumenian standing slightly left, head right, holding signum and scepter; two signa to right. RIC IV 102; Szaivert 9-10; RSC 3b. VF, toned.

From the Olav E. Klingenberg Collection, purchased from Oslo Mynthandel, September 2011.