Product review (4 stars): DANGER- EASY TO LOSE BRUSH IN VENT
DANGER!  DO NOT USE REVERSE (COUNTER-CLOCKWISE) ON THE DRILL! BRUSH WILL COME OFF IN DUCT!  Seems really apparent... but even I didn't think about this being an issue; and I'm usually pretty savvy about this kind of thing. Ending up having to have a professional come clean my vent & extract "lost" brush. Won't make that mistake again... Would be great if manufacturer would include an 'extraction' tool. Otherwise,  great product.