there is a 4 place switch on the back, depending on the position of each one you can set the revs , 3050,4100,5175,6000,6525,7500,8300,8400,9150,10000,10500,11000,12000,12800, abd 14600 rpm
to "program" it, for say 9150 rpm you push thde number 2 and the number 4 switch to the "on" position
its very easy to use.....accel says they will email you an owners manual for it if you ask