Does Anyone Recognize This Stamp

Can anyone help me identify this stamp

"Issued by the government of Spain and emitted by the Postal Mutualidad, this stamp was used as a tax exemption in
the particular correspondence of the personnel of a post office and was also sold to the public for very restricted use. In Spain, the civil war between the nationalists and republicans lasted from 1936 to 1939. Many provisional stamps were issued during this period because the Spanish government could not maintain the national postal system. There are a certain number of these stamps that were issued mostly for stamp collectors simply to generate revenue for the war effort."

From http://www.maf1.com/tsandcc/TSCC-Vol14No3.pdf

(I'm not sure I really understand all this!)

EDIT: To be clear, the above describes a series of stamps issued though references a specific stamp.

In this case, only the first element seems to apply, as the date is long after the fascists' victory in the Civil War.

Tazzman30, I googled the wording on the stamp, and you get an awful lot of Spanish ( which I am awful at ).
Translating through Google does not do much in this case. but one of the items I came up with is that this particular stamp was to help postal workers in case of an emergency.
The stamp KGB is trying to explain is a different one altogether - it was a ten cent label with a picture of a windmill on it.

Peter

The Spanish 1936-39 War aftermath, actually lasted until 1975 (dictator general Franco's death) and, on some aspects, it still goes on.

The stamp is a charity one issued for the benefit of post office workers' orphans. Its "voluntary" purchase was advisible, and it had to be affixed on PO forms if you wanted "to avoid problems" with your shipment, up to the 1980 dècade.

The face value is 50 centimes of peseta. Spanish currency from 1869 up to 2001 (1/166 €). There were 50 cents coins up to the mid 80's. In 1975,a domèstic letter faré was 5 peseta.

The stamp shows a "horreo" a maize storage construction typical of NW Spain.

The value, is minimal.

Thank you, Cursus, that helps greatly.

Peter