Plain cover franked with 1925 5c blue 'Chilean Lapwing' issue and 1926 6c deep blue 'Albatross' issue (SG 480 & 495) tied by MONTEVIDEO roller cancel with manuscript 'Via Aerea' at top left. Flown on the 19 Mar MONTEVIDEO - BUENOS AIRES flight, addressed to BUENOS AIRES with arrival marks on reverse. (Muller #18)