Product review (5 stars): Great tool!!
If you follow the directions this product does exactly what they say it does. Tighten two connecting rod using two wrenches. Then using black tape tape the connections. Using a cordless drill set the clutch at a low level.(2 or 3). Feed the brush into  the vent pipe. If the clutch  makes a noise increase the clutch setting up 1. Then feed the rod into the vent pipe and go slow. Add extensions  as needed following  the above instructions. NEVER NEVER reverse the direction of the drill (counterclockwise). When you have gone far enough start pulling the rods out still going clockwise. If not enough room to pull all the rods out together then  pull out 1 rod and remove the rod from the attached rod. Then pull another rod out and remove it from the attached rod. If the rod binds in the vent pipe STOP!! There is a tool to remove a bind like a bird nest. Pull out the rods and attach the tool to the rod and feed it into the vent pipe again CLOCKWISE!  Go Clockwise, slow, tape the rods, set the clutch low and you should not have any problems.