A Very High Quality Porcelain (Ceramic) B9A Valve Base (Tube Socket) 9 pins.

Bright Nickel plating.

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

Contact resistance: kess than 10milliohms.

For many Mullard, Brimar, Mazda and American Valves inc EF86, EL84, ECC81, ECC82, ECC83, ECC85, ECC88, 12AX7, 12AU7, 12AT7 etc