The Cosmos Radiophone C.1 was advertised in its time as the simplest way to enjoy radio listening. This crystal detector receiver, manufactured by the British company Metropolitan-Vickers between 1922 and 1924, was a tabletop model housed in an elegant wooden cabinet. Remarkably, it required no power source, as it operated using a crystal detector and drew its power directly from the received signal.

The receiver was designed to be used with headphones or an external amplifier. An interesting feature was its dedicated compartment for storing headphones, and it bore the BBC/PMG stamp with GPO No. 145.

Priced at £3.50 upon release, the cost would translate to approximately £525 today—around 16,000 CZK.