Watch List notes:

ROMAN IMPERIAL AND PROVINCIAL COINS

Probus, 276-282. Off metal test strike for an Aureus (Billon, 22 mm, 3.51 g, 5 h), Rome or Ticinum. IMP C M AVR PROBVS AVG Laureate and cuirassed bust of Probus to left. Rev. CONSERVAT AVG Sol standing facing, head to left, raising his right hand and holding globe in his left. Unpublished, but cf. the aurei Calicó 4152a and RIC 308. Of great rarity, with a stern and uncompromising portrait of a powerful general. Dark surfaces with some traces of silvering; very minor flan crack, otherwise, extremely fine.

Ex Nomos 11, 9 October 2015 and from the collection of a European specialist.
This is a very exciting coin. The bust is very carefully done and the ties of the laurel wreath are very distinctively made (cf. the unique quinarius of Probus - attributed to the mint of Rome - that appeared as lot 588 of NAC 54).