Your fuel injected American V-Twin is equipped with an ECU (electronic control unit) that's programmed to deliver fuel to the motor based on an air / fuel ratio for a stock air filter and stock exhaust system. While the ECU can self-adjust for environmental factors such as temperature and altitude, it can't adjust for mechanical changes like adding performance parts. When you install a performance exhaust system, your airflow changes, so you need a fuel management system that adjusts your air / fuel ratio to match the changes. That fuel management system is Fuelpak. The perfect combination with your performance exhaust system. LCD version Fuelpak features finer mapping resolution for greater tuning precision along with improved software to minimize deceleration popping. Throttle position sensor-based system simplifies the process of fuel-injection tuning. Enables you to fine-tune the fuel mixture throughout the entire RPM range with the touch of a button. Increases power and improves throttle response. Very user friendly; plugs into the existing harness on the bike. No computer or software is required, simply punch in the values supplied with the Fuelpak. Values supplied are for use with Vance & Hines exhaust systems. Includes all necessary mounting hardware. Note: Fuelpak maps are optimized to run on High-Flow air filters, but will also run on Stock models. When using a stock air filter, your bike may run slightly rich until you upgrade to a High-Flow air filter.