New-Old-Stock (NOS) tube.

The 5V6GT is a beam power amplifier designed for service in the output stage of 600mA series heater operated TV receivers. It has high power sensitivity and high power output with comparatively low supply voltage. Thermal characteristics of the heater are controlled such that the heater voltage surges during the warm-up cycle are minimized provided it is used with other types which are similarly controlled. With the exception of heater ratings, its characteristics are identical to the 6V6GT.