The Twin Tuner II has all the features of the original Twin Tuner and includes ignition timing control You can easily adjust your fuel injection and ignition to match the requirements of performance parts including high compression heads, pistons, cams, free flowing exhausts and low restriction air filters You can add 30% or subtract 20% fuel and retard spark up to 10° Easy installation only takes 10-15 minutes and requires no splicing, cutting, crimping or bulky interconnections The unit is completely encapsulated and impervious to moisture With a very low profile of only 1/2" it occupies a fraction of the space required by competitors products User interface consists of up/down pushbuttons and bright LED display to select and change fuel trim and spark retard in RPM and throttle position ranges Twin Tuner II also has an advanced mode where you can use the optional USB interface 382-810 and PC Link Tuner software to make precise fuel and spark retard adjustments PC Link Tuner uses the same RPM rows and throttle position columns as the Dynojet Power Commander If you have created map files for your Power Commander you can enter the same values into the Twin Tuner II tables and make individual fuel trim adjustments to the front and rear cylinders Increases horsepower Improves throttle response Eliminates spark knock Easy plug-in installation and setup Very compact size - only 4" Long x 2" Wide x 1/2" Tall Compatible with Twin Scan II+ Tuning Aid Low cost