PECO Perfins on 1927 Cover to New York

In the USPI collection COMMERCIAL SECURITY STAMPS OF THE PHILIPPINES a cover
with 2c Rizal x 2 of the PECO perfin is illustrated. In a sense it is nothing new already. 
However, in its true sense
COVERS WITH PECO PERFINS ARE STILL DIFFICULT TO COME BY THESE DAYS. 

The above cover is added to simply document its existence
and maybe one day we will be able to give a more accurate
estimate of the number of exisiting covers.