Summary

Small output pentode. No data can be found. The 2.5 V filament is very unusual for an English valve which suggests that it was intended as a substitute for an American type.The suppressor grid is connected internally.
Manufacturer: Cossor, England.
2.5 V, 0.7 A directly heated cathode.
The filament voltage and current are hand written on the paper label as is the type number; this, along with the absence of any published data suggests that this may have been a prototype or a custom type made to order.

Physical Description

Conical bulb on four pin UX style base with side contact.

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