Programmable PROCOM Performance CDI for the Yamaha YFZ 450 (04-09) which allows you to adjust both timing and rev limit for the engine. All of the 9 preloaded timing maps provide a 500 RPM increase in RPM limit over stock and can be selected by simply turning a switch dial on the top of the unit. These maps were custom made for this YFZ450 engine and will offers different timing for various conditions. This Procom Performance CDI also has a built in USB port and it comes with Windows software which is very easy to use. Using this software you can adjust timing within a +32/-10 degrees of stock timing at various RPM points and set the rev limit at any value to create a custom map. And it is very easy to switch the unit back to the factory stock condition. Procom also provides its 9 preloaded maps available for download on http://www.procomeng.com This CDI box is a direct plug in replacement CDI. Simply locate and remove the stock CDI, and plug the Procom unit directly into the wiring harness, no modification needed. Suitable for stock and modified machines. We cover all our PROCOM Performance CDIs with a full one year warranty.