The VT-207 is the US Government specification for the commercial 12AH7GT. It has two independent audio triodes within the envelope. The triodes are low impedance, low gain types similar to the ECC82 in ratings. The anode dissipation is 2.5 Watts per anode.
The Ken_rad name on the base and the Type is etched into the glass within an octagon.
The 12AH7GT etched into the glass. The stitched anode is seen behind.
Anode side view.
The wide glass tube envelope is 29 mm in diameter, and excluding the IO base pins is 62 mm tall.
References: Data-sheet, 1040 & 1043. Type VT-207 was first introduced in 1941. See also1941 adverts.
