It should have come with 2 different rubber inserts 1 thick and 1 thin. In order to use it with the iso grips you have to use the thinner of the 2 inserts. The round plastic piece with 3 set screws in it does not go over the flange at on the grip, it just buts up against it.(you will lose about 3/8in of usable grip)Once you have the assembly butted up against the flange you hold it tight and tighten the set screws down on the rubber insert so that it doesn't slip on the grip. Then attach the rest of the assembly and adjust the tension. Hope this helps
I have a BrakeAway Motorcycle Cruise Control and it's pretty awesome. It disengages automatically when I engage the front brake, it's easy to set and permits minor throttle adjustments while engaged. It was a bit pricey but works and wears well and looks good. Fairly simple to install.