The CV1366 is a screened transmitting pentode with the V248A as the prototype. The old Army service code is ATP4. The anode dissipation is 5 Watts.
No maker is indicated but the MO base was used only by Mazda.
The valve has two sections connected internally in parallel.
One pentode section with filament tensions springs above.
The top mica hold the filament springs and the mica disc below has the fingers that grip the inside of the glass bulb. The tops of the grid supports can be seen.
A closer view. The helical springs have a hook in the centre.
The classic envelope is 39 mm in diameter, and excluding the MO base pins is 97 mm tall.
Reference: Data-sheet. Type CV1366 was first introduced in 1940. See also1940 adverts.
