1U4

1.4V @ 0.05A Filament Drive Rail, Sharp-Cutoff Radio-Frequency (RF) Pentode Vacuum Tube [1AD4]. It integrates a close-mesh inner suppressor grid layout designed explicitly to manage high-gain intermediate frequency (IF) amplification loops while entirely shunting out low-level parasitic inter-electrode capacitance anomalies and tracking non-linearity. Housed in an industry-standard 7-pin miniature glass tube envelope chassis layout. Exact part index: 1U4.