Product review (5 stars): They also recommend you use a drill with a clutch (cordless drill) ...
Worked perfectly. Couple of things to note - the vacuum attachment (even with the step down adapter) was too big to fit my shop vacs. It's designed for the larger diameter hoses. They also recommend you use a drill with a clutch (cordless drill) which I didn't have on hand. All in all this did an excellent job and I'd thoroughly recommend it if you're a do-it-yourselfer as over the course of a few years it'll save a lot of money vs. having someone come out and clean the vents.