Wireless World, July 24, 1936.

Valves Advertised:

B21, DH30, DN41, H2, H210, H30, HL2, L21, LP2, MH4, MH41, MHD4, ML4, MPT4, MS4, MS4B, MSP4, MU12, MU14, MX40, N30, N30/G, N31, N41, P2, PT2, PX4, QP21, S23, S24, U10, U12, U14, VMP4G, VMS4, VMS4B, VP21, VS2, VS24, W30, W31, X21, X30, X31, X32, X41.