Cuba, 25 centavos, short-and-thick key incuse countermark (1872-77) on a USA (Philadelphia Mint), seated Liberty quarter dollar, 1858. KM-R4.3. 5.98 grams. Weak but full VF countermark on the obverse of a VG host coin, solder spot on the reverse, popular and important issue from the time of Cuba's "Ten Years War" against Spain (1868-78).
Estimate: 200 - 300 USD