The 7C7 is a sharp cut-off RF pentode on a B8B or Loctal base. The characteristics are close to the older 6J7GT.
The 14C7 is electrically identical with the exception of the heater characteristics - the 14C7 being designed for universal sets with a series connected 160 mA heater chain.
The outer screen covers the rest of the construction.
The mirror dome carries the Type designation.
The wide glass tube envelope is 27 mm in diameter, and excluding the B8B base pins is 53 mm tall.
Reference: Data-sheet. Type 7C7 was first introduced in 1940. See also1940 adverts.
