The INNOVA 3555 Advance Timing Light is packed with advanced timing capabilities which enables users to check base timing, mechanical advance or retard, and electronic advance or retard applications. Direct reading advance scale adjusts from 0-60 degrees. This includes slim, rotating barrel for better aim at timing mark and works with most ignition systems: conventional, electronic, and computer-controlled systems - domestic and import. The INNOVA 3555 also has a Patented Skip Circuitry Test up to 9,990 RPM.