Our MSD Ignition tester makes short order of testing your MSD unit including all rev limits and events.;Hand held tester generates a reluctor signal to check the operation of MSD single channel Ignitions and the coil (6, 7, 8 and 10 Series Ignition Controls); LCD display shows the simulated RPM and can be used to confirm the operation of rev limits, rpm activated switches, shift lights and tachometers; Additional circuit will check the operation of cam sync signals; Reluctors through breaker points, amplifier and magnetic pickup reluctor inputs from the MSD Ignition; Can be used on 4, 6 and 8-cylinder engines;