My apologies guys, I have been out for a while and didn't think I'd get it so I have nothing yet to show. Someone can take my place and post. I'll find something later on
Stecol has it. It is an OSS barometric firing device that functioned on the drop of atmospheric pressure. Secreted in an aircraft with an explosive charge it was designed to operate at about 1500 feet. The SOE device (designed and manufactured by MD1) was the inspiration for the OSS version, the SOE having asked the US to help with production of their 'altimeter' switch. The US version is said to be a vast improvement over the British design, not least that it worked.Is it an OSS/SOE "Anerometer" ?