New-Old-Stock (NOS) tube.

The 6CJ3 is a single heater-cathode type diode intended for service as the damping diode in the horizontal-deflection circuit of color television receivers.

The diffusion bonded cathode practically eliminates one of the major failure mechanisms in damping diodes, which is plate-to-cathode arcing caused by emissive particles being pulled from the cathode by the high electrostatic field.