Twin Tuner II has all the features of the original Twin Tuner and includes ignition timing control capabilityEasily adjusts the OEM Delphi fuel-injection and ignition to match the requirements of performance parts including high-compression pistons/heads, camshafts, free-flowing exhausts, and low-restriction air filters add 30% or subtract 20% fuel and retard spark timing up to 10°You can use the mode and up/down push button switches to make fuel trim adjustments in the rpm and throttle position ranges required by most applications. The fuel trim value is displayed on a bright daylight readable LED displayThe Twin Tuner also has an advanced mode, using the optional USB Interface and PC Link Tuner software to make precise fuel adjustments and allows independent adjustments to the front and rear cylindersMay be compatible with other controller mapsEasy plug-in installation and setup, with no splicing, cutting, crimping, or bulky interconnectionsCompact size only 4" L x 2" W x 1/2" HCompatible with Twin Scan II+ Tuning Aid install the Twin Scan II+ and ride the bike, then copy the air/fuel ratio corrections calculated by the Twin Scan II+ into the PC Link Tuner softwareNOTE: Not legal for sale or use on pollution-controlled vehicles.