The energy from the generator is controlled with Field Effect Transistor (FET) technology, which is far superior to mags still using points as a trigger source. FETs are much more accurate, durable and capable of handling much more current This is why the Pro-Mag is capable of delivering full energy sparks throughout the entire rpm range of the engine, while conventional magnetos fall short of full power at high rpm. Plus, the Electronic Points Box keeps each spark glowing for up to 26 degrees of crankshaft rotation. Another unique feature of the Pro-Mag 12 is a built-in Soft Touch Rev Control. The rpm limit is adjusted with plug-in modules and will save your expensive engine in the event of driveline failure or missed shift. This system provides a smooth, backfire-free limit. The cast aluminum housing of the Points Box provides a strong mounting foundation for the electronics and coil. All of the circuits receive a heavy-duty coating of Humi-Seal for protection against vibration and moistureFeatures:The Points Box has a built-in Soft Touch Rev Control that is adjusted with plug-in rpmThe Points Box controls the spark duration and the unique full power firing of the Pro-Mag 12 and 20.Product Description: MSD Pro Mag 12/20 Amp Electronic Points Box - Black. Ignition Box, Pro Mag, Electronic Points Box, MSD Pro Mag 12, BlackPit Stop USA offers MSD Pro Mag 12/20 Amp Electronic Points Box - Black 81063 at low everyday prices. Be sure to check out all our products from MSD including MSD Ignition Boxes and Controllers.