Tube ID 18R-AL1?

[Trout]

I have been cleaning my tube storage up all day, sorting potentially fun tubes from tubes to put into deeper storage.
After searching many tube data sites, I came across an a sleeve of interesting looking Tubes.
18R-AL1 ?
Sylvania labeled boxes, Sylvania labeled tube import from japan.
Looks alot like a possible triode/pentode combo.
I checked the usual online data sheet sites and I am drwing blanks on this one.
Anyone have a data sheet on this?
Gene

 

[Tom Bavis]

Closest I found was a listing in Precision 660 tube data - appears to be a dual triode with 18V filament.

 

[cpu_bach]

Yes, this is a twin tridode with 18V heater supply. These tubes were widely used for telecommunication equipment for wired telephone systems.
Best regards.