Compañía Armour de Cuba

Armour and Company

also: Compañía Abono Armour de Cuba (Armour Fertilizer)

Mercaderes 15, Havana, Cuba

This firm produced perfins from 1917 to 1928.

Here are a couple of CA perfined covers:

Used 21 June 1922 to Ashville, North Carolina, USA
CA perfin on 2¢ Máximo Gómez definitive (1917) - Scott 265, Edifil 206

Used 10 February 1923 to New York City
CA perfin on 3¢ José de la Luz definitive (1917) - Scott 266, Edifil 207

Here are some of the stamps which have CA perfins.