Originally sold by the mint as a part of a 3 coin set including the J-676 and J-684, the J-666 is a small cent pattern depicting a shrunk down version of the existing three cent nickel design. Graded PR64 Cameo by NGC this well preserved small cent displays cameo contrast, with die polish lines and the usual light contact one would expect for a PR64.

Struck in nickel with a plain edge, the J-666 comes with a few die pairings. Per uspatterns.com, this appears to be the obverse 3 and reverse B variant, with an R6 rarity.