A Very High Quality Porcelain (Ceramic) B7G Nickel Plated Valve Base (Tube Socket).

Test Voltage: 1600V, Insulation resistance >10,000M ohms,

Contact resistance: < 10milliohms. For Many small Valves inc EB91, EF95, Z77, EL90, EK91, EL95, N77, 6AM5, 6AL5 etc.