Vacuum Tube - 6A8GT, Pentagrid Converter
New-Old-Stock (NOS) tube.
Also known by US military identifier VT-151A.
The 6A8GT is a pentagrid converter designed for service as a combined oscillator and mixer in AC, storage battery, and AC-DC operated receivers. With the exception of capacitances, the ratings and characteristics are identical with those of the 6A7.