Watch List notes:

Elizabeth II, fifty pence pieces, 2011 (2), The London 2012 Olympic and Paralympic Games, Aquatics (2), head r., wearing tiara, revs. swimmer submerged in the water – there are two varieties of this coin, one where the swimmer's face is clear of the water, and a much rarer variety where the water lines continue over the face, this lot gives an example of both varieties (S.4961, 4961A), both certified and graded by NGC as Mint State 66 (2)
NGC have identified the varieties 'water lines over face' and 'no water lines over face' on the respective slab cases.
(Estimate: 1000-1200 GBP)