Nope, it's just the Cas9 protein and the guide RNA. The guide tells Cas9 precisely where to make cuts in the DNA. The part that's cut is naturally removed and digested by the cell. Then when that happens, the cell's natural repair mechanism takes the two open ends of DNA and connects them together.

As you might guess there's some work required to figure out dosing. To low of a dose and you probably won't edit enough cells, so the un-cut gene will persist. Too high of a dose and you're probably going to harm the patient or cell.