Issued to honor Cuban Patriots, the three cents is in honor of Julio Sanguily.
SPECIMEN or MUESTRA, usually with a round hole or two, is a stamp or bank note with this legend is one of a few pieces that the printers sent to the Cuban goverment to obtain final approval to print the issue.
Cuban SPECIMEN stamp, 1910. Mint, NH, full gum.
Estampillas MUESTRA de correo cubana de 1910.
Sellos de correo cubano, nuevo, sin usar, con su goma original.