That would be a quick $500 to $1000... You wouldn't happen to have a spare laying around, would you? Ooops, I shouldn't have said that. Now there will be 100's of new competitors.. Good point. Perhaps I will try a smaller opening in my next update. I hate hardware updates....grumble, grumble.... C If they're coupling the pressure sensor to the outside with a fluid, the port may be extremely small- even a tiny capillary would do. Maybe it's there, but hidden or disguised somehow? You could always rip one apart to see... Dave - -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body