The 402P (402.P Thrower) is an indirectly heated output triode. The heater is rated at 40 Volts and 200 mA and was aimed at universal sets without a mains transformer that would run from AC or DC mains.
The B7 base pins. The slots and slight expansion allows the pin to grip the holder.
The top cap connects to the control grid. Looking into the image it can be seen that there are two grid windings at different distances from the cathode.
Thanks to Mark Mallison for sending the images.
The classic envelope is mm in diameter and, excluding the B7 base pins, is mm tall.
References: Data-sheet & Data. Type 402P was first introduced in 1934. See also1934 adverts.
