Dean 'Gem' pocket reciever, 1924. Also known as the Dean miniature portophone broadcast receiver.

In the 1920s Frank L.W. Dean and his brother ran a retail wireless business in Cardiff, South Wales. In their workshop they designed and made a range of miniature radios at a time when most sets were large and sprawling. Though cleverly constructed and well marketed, they were fairly expensive, and few were sold.

From Dean Gem Portophone Company document: All the BBC stations have been received on one of these sets but they are not guaranteed to receive all of the BBC stations. Signals from at least four of the BBC stations should be received and continental broadcasting has been received on these sets at Cardiff, while Bournemouth was received in Cardiff at almost loud speaker strength. The wonderful sensitiveness of these sets when it is considered that only one valve is used can be appreciated by actually listening in on one. Weather conditions immaterial. No danger from lightening. Set was provided "complete with [headphones], batteries, valve, BBC taxes etc."