1 tube type 42 Fivre made in Italy old production 1940's 

black round plate 

copper rods 

squared getter 

coated glass 

brown base 

Fat ST shape 

yellow label wide 

internal coated glass 

pure pentode for last stage audio or driver tube for exotic project DIY 

tested on tube tester TV7D/U = 92 (reference good at 50) 

Power Output pentode 

42 = UZ-42 = UZ42 = A642 = 42S = W2160 = NU-42 = VT163_GPO = CV1712 = ER42

Similar tubes  Other shape (e.g. bulb type):   M42

Sub tube:   38042 ; 42E

Other class quality (otherwise equal): 1615 ; CV609

Different maximum ratings:  293A_WE

Heater different:   18 ; 2A5

Other wirings:  6P6_AUS

Other base:   42_Octal ; 6F6G

42 tube is the previous version of 6F6G / 349A WE 

Socket is 6-Pin-Base U6A, old, USA 

Filament Heater is Vf 6.3 Volt / If 0.7 Ampere / Indirect 

box 183

cod 2