The 5CG4 full wave rectifier has a maximum PIV of 1,400 Volts. The overall parameters place it as just below the rating of the GZ34 another 5.0 Volt heated rectifier.
The stitched anode plates have a central flange facing the envelope wall.
The construction is an indirect heated rectifier but joining the cathode to one side of the heater removes the issue of heater/cathode breakdown voltage. With a 5.0 Volt heater this rectifier would be normally coupled to a transformer winding especially for the rectifier.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 72 mm tall.
Reference: Datasheet. Type 5CG4 was first introduced in 1957.