Product review (4 stars): Works Great, Just Use Common Sense When Doing It!!!
Great product but they need to include more rods in the kit. I had to buy a second set of rods and that still wasn't enough so Ill end up spending $60+ dollars on this kit which isn't terrible if you factor what you would get charged out in town, but still, its plastic rods with a brush attached....thats overpriced for something so simple.

So enough of me complaining about it being overpriced and get to the review. It works GREAT if you aren't an idiot and use common sense when using it.

1.  Always CLOCKWISE..... again always CLOCKWISE, I cant be anymore clear about this.
2.  Use electrical tape or duct tape as a backup in case you screw up on number 1 above. Its a good safety measure so just do it, it only takes a few seconds per rod to wrap in tape.
3.  Feed one rod at a time, taping each one as you go.
4.  Dont force the rods if you get resistance with the drill attached. If you get resistance, remove the drill from the rod and using your hands wiggle/shift the rods until you get past the resistance and then reconnect the drill and continue. Most likely if you reach resistance is likely one of two things. (1) You have a large bend in your duct or (2) you have a lot of blockage. If its number 2, start pulling the rod out (with or without the drill attached (if the drill remains attached, remember to always spin  CLOCKWISE) as youve probably hit a patch of lint clogged heavily in one area. Pulling the rod out will likely pull a large portion of lint youve broken loose out with the rod and brush  attachment so vacuum it up or blow it out if you have a leaf blower and then start again (I didn't disconnect rods during this step but I did take my time to hand feed the rod and brush back in to ensure I didn't damage the rods).
5.  Once youve reached the end of your vent, start pulling your rods out the same way you went in (CLOCKWISE) so that you catch any debris you might have missed on the initial cleaning.  I pushed the brush through 2-3 times in total from different sides of the vent since I was short a few rods and used the leaf blower 4-6 times in between to ensure I was pushing any lint to the exterior of the house (never blow the leaf blower into the house, only blow to the outside of the house unless you want a HUGE mess in your house.
6.  Lastly, Id recommend using a face mask/respirator mask as this stuff is messy and you don't know whats growing in it. I had some cheap carpentry mask but will use a better version next time I clean it as its not fun to breath in.