Four Number 42 power output pentodes.

Four 6 pin tube sockets to match the tube base and four retainer rings to secure the tube sockets in a chassis.

These were tested in an amplifier i built for plate current draw and screened for microphonics.

As well they have been tested on my Hickok for mutual Conductance.

Tube -1 RCA

PV=302.1 VDC

mA= 44.3

GM= 660

Tube -2 RCA

PV= 297 VDC

mA= 48.1

GM= 650

Tube -3 RCA

PV= 304.5 VDC

mA= 39

GM= 660

Tube -4 Ken Rad

PV= 299 VDC

mA= 51.3

GM= 680

I have many other tube amp parts and components listed, please see my other items if you like.