Since it holds your 1st gear and reverse gear both at the same time, the trans isn't going anywhere. That gets your stall speed where you want it everytime. Most foot brakes will not hold your trans till it's flash stall speed due to the high horsepower of your high compression drag engine. The reverse pressure is redirected by a solenoid activated by 12v through a simple switch or a delay box. Turn off the 12v and the reverse pressure dumps back into the pan. I had to drill a small hole at the rear of the case to install it's wire.
Listen to the Super-PRO bracket racers at your local track. Before you see the lights coming down, we held the throttle to the floor when we were ready for them to start the tree. The Rev limiter and transbrake held everything right where we set it till we let go of the button. The 2-step rev limiter's lower setting controls your lower launch rpm. That's when all action starts and the car takes off. If you can control to the .001 of a second when you car lauches, that is what gives you an advantage over the guys without a tranny brake. Winning the races, wins you the money. In bracket racing, you don't have to be fast, you have to be consistent.
Rob