General Electric 6AU5GT beam pentode
The 6AU5GT is described as a beam pentode and was designed for line output service in television receivers. An alternate design use is as a series pass device in regulated power supplies. The 6AU5GT has a 10 Watt anode dissipation. The top view shows the heat sink fins attached to the grid support rods.
The wide glass tube envelope is 29 mm in diameter, and excluding the IO base pins is 65 mm tall.
The 6AU5GT was first introduced in 1949.