Original Marconi Osram ML4 AC/P tube
      Indirectly heating triode
Vf=4V, If=1A 
AC/P CV1179 NR57 CV1732 10E/17 VT90GPO VT129GPO
 the tube seems to be slightly used, high emission:

tested in conditions: f=4V Ua=150V Ug1=-6V
 Ia = 20mA
where 100% for the new tube is about 18mA
the tube has Europe 5-Pin (B5, O5A) base

The ML4 is indirectly heated amplifier triode.

Perfect driver for PX25 PX4 tubes
you will get the tube you can see at the pictures
I always send the tubes by priority registered mail with tracking number within hours after receiving payment

                                                                                                                Santic [feat. Vera Hall] – Trouble So Hard