![](https://coimages.sciencemuseumgroup.org.uk/50/675/large_thumbnail_1972_0141_0248__0002_.jpg)
Wade Bequest collection of valves: small triode radio valve, by Marconi-Osram
- PART OF:
- Wade Bequest collection of valves
- Made:
- 1921 in England, Germany and United States
![SMG00237631](https://coimages.sciencemuseumgroup.org.uk/448/592/medium_smg00237631.jpg)
Wade Bequest collection of valves: small directly-heated triode radio valve, by Marconi-Osram. With B4-3 base and top seal. With paper label: 1921