43IU Cossor black ribbed plate full getter B4 base MU12 MU14 IW3

Description

The 43IU here shown are the very early design made by Cossor.

We understand the 43IU was introduced before the 53KU keeping the same design and changing the base to an octal one, rest is similar.

Needless to say the 43IU can be considered the father of the 53KU.

The pair here shown are not for the  faint hearted! This is a serious valve made by Cossor with black carbon plate and oxide filament.

The 43IU is an indirectly heated full wave rectifier.

Both 43IU have been tested 100% emission and in working order.