COLOMBIA. Costa Rica. (1889) counterstamp on Colombia 1879/4 Medellín 5 Decimos. KM-135.2. EF Detail — Cleaned, C/M AU Detail (PCGS).Very appealing medium gray with very subtle hairlines and a natural appearance. The reverse mark is a bit soft at top, but the obverse mark is complete and bold. A very attractive and high grade piece.