AUTHENTIC MAGNUM REVOLUTION-PRO. PROGRAM YOUR IGNITION, RPM & SPEED LIMIT WITH TWO MINI BUTTONS EVEN DURING THE RIDE. REVOLUTION PRO-II is a special adjustable digital VCXO (Voltage-Controlled Crystal Oscillator) with uniquely extended frequency range, developed to fuel injected ATV engines. It plugs to the ECU's factory quartz. A quartz also referred to as crystal oscillator is a tiny electronic oscillator circuit that applies the mechanical resonance of a vibrating crystal of piezoelectric structure to produce an electrical signal with a very precise frequency. This frequency is used to keep track of time to provide a stable clock-signal for digital devices as PC. This PROGRAMMABLE chip allows you to raise RPM & speed limit by up to 20 % while remaps ignition timing & advance. REV-Pro is the best choice to harmonize the engine management with further performance parts preinstalled as exhaust, intake, fuel programmer, etc. in order to achieve ultimate power. MAGNUM developed this CDI box to comply with electronic management system requirements of tuned engines accordingly highly recommended to wire up a fuel controller in advance. Though the unit installs easy & FULL INSTRUCTIONS INCLUDED & even people who are slightly technically inclined will find, chip is not difficult to wire up, dismantling of ECU still required accordingly we strongly recommend having a certified tech install this unit if you are not experienced with basic electronic jobs. Before purchase open up ECU and check whether you are able to remove the silicon seal - applied on some models - from inside because you need to access to the factory quartz crystal. Magnum TuningTM has been dealing with manufacture of upgrades since 1994. Magnum's experience warrants peak performance, reliability & perfect style. Magnum Parts are made in Europe & covered by 10-YEAR WARRANTY.