15c lilac postal stationery registered envelope (H&G C1a) demonetised with 'SIN VALOR' overprint in black on front and reverse used with added Argentina 1912 pair 1c yellow brown, pair 4c dull purple and pair 20c ultramarine 'Ploughman' issue (SG 396, 399 & 403) tied by BUENOS AIRES cds's dated 11 MAR 1915 with printed black on white 'BUENOS AIRES' registration label alongside. Addressed to SWITZERLAND with arrival cds on reverse. Cover has a few light tones on reverse but otherwise a very scarce item of postal stationery in used condition and highly unusual used in Argentina.