Los 999
Provisionals red Typewriter Surcharge: November 1920, "VALOR $0.10" in red on 50c. pale green with two-line cancel "NAVEGACION AEREA NEIVA" and tight by oval cachet to cover to Bogota, used in combination with Colombia 1917 ½c. yellow-ochre as strip of four and pair, a rare and appealing cover, certificate PF (1996)
