Product review (4 stars): I discovered a bird's nest!
This product is for sale at a ludicrous price on Amazon UK, but delivery from Amazon.com was quick (3 days) and easy. There's not a great deal to to this kit, but the key thing the pieces give you what you need and it works. The accessories, like the Vacuum+cleaner rod-to-4" pipe adapter, are just thin plastic mouldings, but they make the job much easier and for a job that realistically you are not going to be doing very often they are a great addition.

I used this kit to clean the ducting behind the extractor fan in our bathroom, in preparation for replacng the fan, and on top of the soap dust (which I expected) I discovered a bird's nest in the pipe, which I didn't!

There are a couple of things to be careful of-

This is a lightweight tool. The rods are thin and flexible. You need a drill with both speed and torque control, and you need to to feed the rods into the ducting gently one at a time, as the instructions that are supplied describe. Get too aggressive with the drill power, or too impatient, and the rods will tie themselves (and you) in knots.

Also, if you drill is reversible you need to BE CAREFUL. The rods screw together, with no locking nuts. If you are in the habit of flipping your drill or electric screwdriver into reverse when you go to remove a drill bit or screw you MUST not do this, or the rods will unscrew themselves and you will end up with the brush and one or more rods left inside your ducting. You have been warned!

The instruction in the kit recommend using adhesive tape to lock the rods together. That would work but it would be a pain to connect and disconnect the rods as you feed them into the duct. Personally I chose to not do this, and just recite "clockwise only" to myself every time I stopped or started the drill, but you need to know yourself and your tools. If you frequently flip your drill into reverse for other jobs, use tape on the rod joints for this one!

Overall great little tool though, as long as you use it correctly. We would probably never have discovered that bird's nest without it.