The 6N9P is the Chinese Type designation for the 6SL7GT medium impedance double triode. With a gain of 70 it was designed for voltage amplification in audio amplifiers and/or as a phase inverter.
The double triode is mounted on the pinch and each heater is a single hairpin and not helically wound.
The grid can be seen on the right hand triode above the mica sheet.
The construction matches the original design in overall appearance.
A closer view of the lower mica and the spot welds that attach the main assembly to the wires secured in the pinch.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 64 mm tall.