Tacitus AE Antoninianus, Ticinum or Siscia.

Obv: IMP C M CL TACITVS AVG, radiate, draped, cuirassed bust right.
Rev: FELICITAS AVG, Felicitas standing left holding long caduceus 
and cornucopiae. 

Officina letter P, S, T or Q in exergue.
RIC V-I 136. 

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