Watch List notes:

Cuba, 4 reales, castle and key countermark (1872-77) on a Zacatecas, Mexico, 4 reales, 1848, PCGS VF details / damage. KM-unl (cf R2). An unlisted and presumably very rare countermark consisting of a small castle atop a short key inside a tri-lobe incuse punched in the middle of the Liberty cap of the well-toned host, above a crude hole at edge, the castle and key a traditional symbol for Cuba and likely the "first attempt" at a countermark for this issue, which was believed to be a fund-raiser for troops during Cuba's "Ten Years War" against Spain (1868-78). PCGS #37523540.

Estimate: $500-1000