Product review (4 stars): Almost a 5 - just a couple issues...
First of all, this thing works GREAT!  I couldn't believe the amount of lint this pulled out of my vent duct, and I feel safer drying clothes now.

However, there were a couple problems. First of all, one of the extension rods twisted and broke off inside my vent duct. It couldn't handle the torque from the drill, I guess. Luckily, it broke off close enough to the opening that I could reach it and pull it out. Another of the rods twisted into a pretzel and was too deformed to use. That one was probably my own fault for trying to shove two rods in right behind each other instead of hooking and unhooking the drill to each separate rod.

That brings me to my final issue with the product - it didn't come with much in the way of instructions. I found a helpful YouTube video, but here are a few tips if you try this out for yourself:  It says you can use with or without a drill... Good luck without one! Unless you have a very short and straight dryer vent duct,  you will need the drill to get it through there. Use the drill,  and reattach the drill to each extension rod. As I learned, if you take a shortcut and use two rods at once, there's too much slack. The drill will twist the rod up. Oh, and when you're done, you will need a couple of wrenches to get the rods apart. The drill tightens them together pretty well.

I do highly recommend this product. Enjoy!