Watch List notes:

Agrippina I. Died A.D. 33. Æ sestertius (35.9 mm, 28.82. g, 7 h). Rome mint, Struck under Claudius, A.D. 42-43. Rare. AGRIPPINA M F GERMANICI CAESARIS, draped bust right / TI CLAVDIVS CAESAR AVG GERM P M TR P IMP P P, around large SC; NCAPR within rectangular countermark. RIC 102 (Claudius); BMCRE 219 (Claudius); Pangerl 1. Fine, rough surfaces. 

The meaning of this countermark is uncertain. Several explanations include: "Nero Caesar Augustus Probavit", "Nero Caesar Augustus Populo Romano", or "Nerva Caesar Augustus Probavit". The origin is also uncertain; it could be either Italy, Gaul, or Spain.