The first of six patent numbers printed in silver ink around the glass envelope.
overall: 5 5/8 in x 1 5/8 in x 1 5/8 in
This object is a xenon triode thyratron with a center-tapped filament in a glass envelope with a medium-metal-shell small four-pin bayonet base and a cap for the plate at the opposite end. The circumference of the base is metal, with a ceramic bottom through which the pins project. There is a small protrusion on the side of the base positioned between pins 2 and three. The tube is rated at 900 V forward voltage at 2.5 A continuous current.