New-Old-Stock (NOS) tube.

The 6136 is a miniature sharp-cutoff pentode designed primarily for use as a high gain radio-frequency or intermediate-frequency amplifier. Its low grid-plate capacitance and high transconductance make it especially suited for high-frequency wide-band applications.

Analysis of the electrical characteristics of this tube with those of the 6AU6 will indicate that the 6136 is essentially similar. The 6136 is a special quality tube intended for use in critical industrial and military applications in which operational dependability is of primary importance. Features of the tube include a high degree of mechanical strength and a heater-cathode construction capable of withstanding many thousand cycles of intermittent operation. When used in on-off control applications, the tube will maintain its emission capabilities after long periods of operation under cutoff conditions.