<html><head></head><body><div class="yahoo-style-wrap" style="font-family:times new roman, new york, times, serif;font-size:16px;"><div dir="ltr" data-setdir="false">Alan, almost all the rebreather galvanic sensors have quick disconnect adapters. I think I'm going to deal with calibration by fabricating a small handheld analyzer that I can connect the same sensor to outside atmospheric air and then reconnect back to the main processor in the vessel. The more I think of it, I will probably just make this handheld O2 sensor a separate physical module that can run on it's own power and "plug-in" to the main processor. For example, something like the "el cheapo" from oxycheq that could connect to and direct it's output to the main processor. This approach would work for the CO2 sensor as well.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Jon</div></div></body></html>