Includes everything you will need to build your MegaSquirt Flyback board using the case as the heat sink.
MegaSquirt (PCB2.2) users running a number of very low impedance injectors have reported problems with the flyback circuit failing. Typically, this will happen with 4 or more low-impedance injectors, such as the Holley 85 lb/hr TBI injectors. This can be avoided by using resistors in series with the injectors, and disabling the pulse width modulation (PWM). However, a more elegant solution that continues to use PWM is to use the Flyback Board. See THIS ARTICLE for pictures of an assembled unit and useful install tips.
You do NOT need this if you are using a MegaSquirt equipped with the PCBv3.0 or later, this is only for PCBv2.2 users running low impedance injectors!