Watch List notes:

MS61 | The Undated Mule | Elizabeth II (1952-), Undated Twenty Pence, [2008], edge plain, 4.99g, 12h (S.G4A [4631A]), the first currency coin struck without a date for circulation in Britain since the reign of Charles II, a famous modern rarity, green depositories to obverse, otherwise much as struck, in NGC holder, graded MS61 (Cert. #6295118-018).

Estimate: £50 - £80