AT Series Æ As. Rome, 169-158 BC. 25.23g, 31mm
Laureate head of Janus; I (mark of value) above / Prow to right; AT (ligate) above, I (mark of value) before, ROMA below. 

Crawford 192/1; Sydenham 372; RBW 821; ; Sear RCV 707

This coin published in Richard Schaefer's Roman Republican Die Project (RRDP), binder 8, p. 94, available online at: http://numismatics.org/archives/ark:/53695/schaefer.rrdp.b08#schaefer.rrdp.b08_0111; 

From the Andrew McCabe Collection
Roma Numismatics Ltd - E-Sale 93, Lot 882, Jan 2022.