Cover franked with pair 1922 1p brown & blue (SG 255A) tied by light strike of boxed 'SERVICIO POR EXPRESO' cachet in black with additional fine strike alongside with '14' express number inserted in manuscript and large 'Oficina de Poste Restante (Servicio por expreso)' label attached on reverse with the sender and addressee details and a third strike of the express cachet. Addressed locally. Fine and very rare, thus far being the unique example of Paraguayan express mail.