New-Old-Stock (NOS) tube.

The 6414 is a heater-cathode type, medium-mu double triode of miniature construction. This type is characterized by long life and stable performance. The tube features a high zero-bias plate current, a sharp cutoff characteristic, and separate cathode connections for the two sections. It is especially designed for use in electronic computer applications and other "on-off" control applications requiring long periods of operation under cutoff conditions.