EL SALVADOR. El Salvador - Mexico. Real, ND (1868). PCGS Genuine--Environmental Damage, Poor/Fair Details; Countermark: Good Details.
KM-Unlisted. Type V countermark applied to the obverse of a Mexican "cap & rays" issue (cf. KM-372 [for type]). Undoubtedly a host which has seen both extensive wear (almost to a blank disk save for a characteristic ray and the "20 Gs" near the edge visible) and some environmental issues, it is nevertheless also a host that is RARELY seen for this countermarked series.
Estimate: $40 - $60