10c blue postal stationery envelope (H&G B9) used with added 1923 30c dull blue SCADTA issue (SG 41) tied by BOGOTA SCADTA cds's dated 4. XII. 1924 with small italic 'Despachada en hidroavion' marking in purple alongside. Addressed to BIRMINGHAM, UK with fine strike of boxed 'Use the Colombian Airmail ! It saves you 10 Days ! Information and Stamps Langstaff, Ehrenberg & Pollak, Liverpool' British consular agents cachet in black on reverse.