Mazda TP22 triode-pentode

The TP22 is a 2V filament battery triode-pentode frequency changer. The triode and pentode are separate and the pentode has vari-mu characteristics. This valve is on the horrid British 9-pin (B9) base. These are almost impossible to insert if the view of the socket is at all obscured, as it often is in sets of the 1930s