The 12AH7GT 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 RCA logo.
The anodes seen end on.
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 12AH7GT was first introduced in 1941. See also1941 adverts.