I have had many interactions over the past 20 years with John, Owner of GaugeTec. Although I did not receive my Backflow Testers certification thru John, I did attend a Surveyors course and have consulted with him regarding cross connection issues that my techs and I have encountered in the field. I consider him an authority on the subject of all things related to cross connections, and value his input. GaugeTec is my instrument testing, repair, calibration and certification company and I am very confident my equipment is field ready and accurate.