The 117P7GT is an American audio beam tetrode and half wave rectifier for use in domestic radio receivers. The audio output is given as 850 mW and the rectifier has a maximum output current of 75 mA. The heater is designed to operate directly across the mains input without the need for a mains transformer.
This exhibit is branded Emerson a radio manufacturer famed for their cabinets made from Calalin - the brand name for a thermosetting polymer developed and trademarked in 1927 by the American Catalin Corporation of New York City. This phenol formaldehyde resin was typically seen in splendid translucent colours as it did not contain carbon or wood flour filling like opaque Bakelite.
The Emerson Brand. The valve looks to be of RCA origin.
Trying to maintain brand loyalty.
The control grid has the ring heat sink attached to both copper support rods.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 71 mm tall.
Reference: Data-sheet & Wikipedia. Type 117P7GT was first introduced in 1940. See also1940 adverts.