This exhibit is a Moorhead B fitted with a British B4 base cap. For the development samples the B was fitted with the American Shaw Base (See the PDF below).
Both the Moorhead R and B exceeded British Army expectations and were very well regarded.
The B had a low vacuum for use as a detector. The anode voltage range was 18 - 40 Volts.
The wording around the base cap reads: This Moorhead valve is licenced under the Fleming patent - number 803684. Other patents pending.
The construction matches that of the standard hard R Type. The Moorhead R Type had a vertical anode.
The etched identification. Within the circle the name Moorhead is accompanied with USA and San Francisco - plus the Cap B.
The balloon envelope is 54 mm in diameter and, excluding the UV base pins, is 92 mm tall.
