Watch List notes:

STUART. Charles I. 1625-1649. AR Threepence (19mm, 1.45 g, 5h). Aberystwyth mint; im: open book. Struck 1638/9-1642. Crowned and mantled bust left; plumes to left, III (mark of value) to right / Coat-if-arms; plumes above. Brooker 774 (same obv. die); North 2340; SCBC 2894. Richly toned, slightly irregular flan. Near EF.

From the New Horizons Collection, purchased from Hammered British Coins.