![](https://coimages.sciencemuseumgroup.org.uk/58/890/large_thumbnail_1991_0166.jpg)
McVitie Weston valve collection, Osram valve, type PX4
- Made:
- circa 1932
- maker:
- Osram
![Osram valve, type PX4, oblique box-shaped electrode system](https://coimages.sciencemuseumgroup.org.uk/457/586/medium_smg00283638.jpg)
Osram valve, type PX4, oblique box-shaped electrode system, (RMW/Y46 - McVitie Weston number), by Osram, c. 1932.
Osram valve, type PX4, oblique box-shaped electrode system, (RMW/Y46 - McVitie Weston number), by Osram, c. 1932.