The PC97 is an RF amplifier triode. It has a high mutual conductance and could be used as a signal pre-amplifier. Its design use would be in domestic television receivers.
The PC97 is a frame grid triode that in addition to a very high mutual conductance of 13.00 mA/V has an unusually low grid to anode capacitance of about 0.5 pF. This low capacitance is obtained by using a special shield between grid and anode in conjunction with a shaped anode. Because of this shield that is in place except in the active cathode to anode region these valves are also known as Beam Triodes. An additional benefit is that the neutralising capacitor can be connected to ground on one side.
The anode side view.
The anode face view. The shaping is just visible in the full sized image.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 47 mm tall.
References: Datasheet & 1040. Type PC97 was first introduced in 1961.