3S4 Power Amplifier Pentode Tube. Designed for operation in low power scenarios such as in compact mobile equipment. MFR: GE, RCA, Raytheon, Sylvania. SKU: 3S4. New old stock. No longer available for
NOS in Box Philco Early 3S4 Tube - Etsy Denmark
2 Tung-sol 3S4 Vacuum Tubes Valves Lot of Two - Etsy