The OS40/1250 is a transmitting pentode normally used as a power oscillator. The anode dissipation is about 50 W. This valve is similar to the RCA type 804.
Thanks to Fred Schneider for sending these images.
The ceramic insulators point to the high anode voltage. The anode is carbonised and the other electrodes are hidden by the bright screening box.
The original Tungsram box.
The wide glass tube envelope is - mm in diameter, and excluding the UX5 base pins is - mm tall.
Reference: 3002. Type OS40/1250 was first introduced in 1947. See also1947 adverts.
