Retro Vacuum Tube Night Light - 3S4 Electron Tube | eBay
2 Tung-sol 3S4 Vacuum Tubes Valves Lot of Two - Etsy
1pcs - 3S4 Vacuum Tube USA | eBay
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