The 6C45PI is a UHF single triode with a central frame-grid and anodes each side of the cathode. Modern use of the valve would be as a voltage amplifier in low level audio circuits.
The anodes are shaped to present a small flat surface close to the grid with the main mass away from the central area.
I the centre is the frame-grid but the wire is too fine to be resolved by normal macro-photography.
The thin glass tube envelope is 22 mm in diameter, and excluding the B9A base pins is 46 mm tall.
