50 Centimos Barcelona; Sindicat Obrer de les Aigües de Barcelona

The Sindicat Obrer de les Aigües de Barcelona — the workers' union of the Barcelona water utility — issued fractional emergency currency during the acute coin shortage of 1936–37, when the Republican government had lost effective control over metallic circulation and collectivized enterprises began printing their own vales and tokens to make change. This note is one of several such emissions by utility and transport unions operating under anarcho-syndicalist self-management following the July 1936 revolutionary upheaval in Catalonia.

Imprenta Martí, Marí y Cia. handled a number of these local emergency pieces during the same period, working under considerable logistical pressure as Barcelona's commercial infrastructure was being reorganized from below.