The type 41 is a high gain audio output pentode that is electrically identical to the type 6K6GT. It was designed for single ended or push-pull use in the output stages of domestic equipment.
The Triotron brand printed on the envelope. Note the use of 'Foreign' not imported. The BVA protecting the home industry?
The wire grids of the pentode and the white of the cathode coating can be seen. The copper control grid supports are topped with a U shaped radiating fin. The springs on the outside of the top mica hold the electrodes firmly to the shoulder of the envelope.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 87 mm tall.
References: Data-sheet, 1040 & 1043. Type 41 was first introduced in 1936. See also1936 adverts.
