The Cossor P2 is a bright emitter valve and first went into production in 1922. Cossor launched the valve as for HF use. This exhibit is of later manufacture and is fitted with a composition base and arrived in an original box. Our other P2 is earlier and has the plated base shell and its box was of heavier construction.
The anode is a parabolic cover over a fan shaped grid and the filament would have arched through the grid from one support to the other.
The grid is a series of wire loops secured to a frame by bent over lugs. This looks very labour intensive.
A closer view of the grid loops and the method of fixing to the support frame.