2p 50c brown postal stationery notification envelope (H&G NB1) with 'CORREOS NACIONALES SERVICIO INTERIOR' overprint in black (Guatemala Handbook Type F). A fine used example with GUATEMALA CITY machine cancel dated APR 10 1931 and circular 'INSPECCION DE CARTEROS DE CERTIFICADOS GUATEMALA' cds both on front. Addressed locally within GUATEMALA CITY.