![](https://coimages.sciencemuseumgroup.org.uk/52/717/large_thumbnail_1922_0732__0001_.jpg)
Wade Bequest collection of valves: early triode radio valve by Marconi-Osram
![SMG00237650](https://coimages.sciencemuseumgroup.org.uk/448/611/medium_smg00237650.jpg)
Wade Bequest collection of valves: early directly-heated triode valve by Marconi-Osram with phosphorous getter. With B4-3 base and pip top. With paper label: W64.
Wade Bequest collection of valves: early directly-heated triode valve by Marconi-Osram with phosphorous getter. With B4-3 base and pip top. With paper label: W64.