The SymTech Labs Sequential Fuel Injection Kit includes one SymTech Labs Peak & Hold Injector Driver Board and one SymTech Labs Hall/Opto Cam Sync Input Module. This kit is perfect for taking advantage of the sequential fuel injection feature in the MS2/Extra firmware. Simply install both modules in your MegaSquirt ECU, perform two quick modifications to your MS2 processor, and then begin enjoying the benefits of fully sequential fuel injection!