This handy controller lets you change the launch rpm setting of the Programmable 7 Ignition Control manually when you're strapping in the car. The controller plugs into the MSD Programmable Ignition Module through the 9-pin harness. There are two control knobs, one for 1,000rpm and the other for 100rpm. The launch setting can also be adjusted from 3,000 to 12,500 rpm in 100 rpm increments.