The 6L6G it is a larger more powerful audio beam tetrode than the 6V6 receiver type. This was used for audio amplifiers and modulators for small Amplitude Modulated transmitters.
This was made in USA and the size and Type designation logo match the RCA 6L6G exhibit we hold.
The Amerty branding indicates a valve made in USA for Mullard - probably during WWII.
The stitched anode and heat radiating fins on the control grid supports.
The classic envelope is 51 mm in diameter and, excluding the IO base pins, is 116 mm tall.
References: Data-sheet, 1040 & 1043. Type 6L6G was first introduced in 1936. See also1936 adverts.
