i found these wbo2 meters, quite interesting, something to check out.
http://www.a-and-t-labs.com/M-2_OxyAny/M-2.htm
http://www.plxdevices.com/
http://www.techedge.com.au/vehicle/wbo2/default.htm
http://www.a-and-t-labs.com/M-2_OxyAny/M-2.htm
http://www.plxdevices.com/
http://www.techedge.com.au/vehicle/wbo2/default.htm