Hi guys For those looking for a differential pressure guage, I have got an "RS" catalogue at work in which I remember seeing a really tiny differential pressure instrument. It looks like a plastic casting with two "nozzles to attach the two sources of pressure. These are electrical instruments which I think have an output of 4mA - 20mA which will need some sort of anunciator on the panel. I will check it tomorrow (If I remember). Regards Dene Collett South Africa KR2SRT builder mailto: dene.coll...@telkomsa.net www.whisperaircraft.co.za