This valve continues the 6L6 family, and is an all glass construction fitted with an octal base, the other designation on the envelope is 6L6WGC. It is a reasonably powerful audio beam tetrode and is used, for audio amplifiers. Chelmer Valve is a re-seller.
The side of the anode has slots through which the grids are visible.
The working face of the anode is also where the two halves meet and the central flange is both used for fixing and cooling.
A close-up view of both the control grid and screen grid. Below the mica can be seen the tapes that are spot welded to the electrode assembly and also the pins. The composite pin can be seen with the red-platinum portion within the glass.
A close-up of the top mica. The cooling fin for the control grid can be seen in the centre of the image.
A close-up of the base.
The wide glass tube envelope is 37 mm in diameter and, excluding the IO base pins, is 83 mm tall.
References: Data-sheet & 3002. Type 5881 was first introduced in 1954.