A Very High Quality Porcelain (Ceramic) B9A Valve Base (Tube Socket) 9 pins for printed circuit mounting. Heavy gold plating. Test Voltage: 1600V, Insulation resistance >10,000M ohms, Contact resistance: < 10 milliohms. For many Mullard, Brimar, Mazda etc valves inc EF86, EL84, ECC81, ECC82, ECC83, 12AX7, 12AU7, 12AT7 etc. Printed circuit Mounting