After purchase and installation of two Teleflex 62724P tachometers I have observed them to be inaccurate in the RPM . While following the manufactures installation guidelines and precision adjustments the tachometers do not "zero out" in a matching level. Both tachometers were initially set up with a diagnostic tachometer and have the correct RPM at idle. The RPMS above 4000 the tachometers have a differential in RPM of around 200. They are not as exact as the Quicksilver tachometers I removed.