If you are running a MSD ignition then don't waste your money on the inductive clamp attachment it don't work with the multiple spark, I had to hard wire mine into the tach out put with the analog cable and just leave it in the car,, now if you are going to use it on multiple vehicles with factory ignition you will be fine with it, I love mine

Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.