I had one but never installed it. The knob on the device allows you to fine tune the release rate and therefore amount of slip.

Push clutch in, hold button, let foot off of clutch pedal. Put the car on the 2 step and release button when ready

 

Someone has to have ran this.

 

I know has it in his both drag cars , he showed it to me in person and demonstrated its use .

 

sub'd for results!