We had an unpleasant odor coming from most of the bathroom sink drains in the house we just bought. The drains seemed to work fine, they just smelled bad. After chemical drain cleaners didn't clear the problem, I tried using this brush.This thing worked like a champ for the main sink drains. I removed the sink stoppers, and I was able to clean the drain pipe down to half-way through the trap. I was very happy. But the smell was still there. It was then that I realized that the problem was in the sink overflow drains.After some trial and error, I figured that the best way to reach our overflow drains is from the bottom up. I took out the drain stopper and ran this brush up from around the base of the sink. This involved lubing it up with some dish soap and bending it to go around corners the way I needed. It was generally very successful. Well worth the price.I have a few minor complaints with this product:1) I wish it had a plastic coating over the metal tip to help it slide around corners in the drain a bit easier.2) It's a little stiff for cleaning overflow drains. You have to bend it before inserting it into the drain, and if there's anything like an S shape or right angle to make, it's nearly impossible to get it to go there.3) The bristles are a little short and tend to remain flat after being pressed while going around a drain corner.4) The metal spine of the brush broke while cleaning the third sink. While ideally it would never break, I did bend it many different times and in many different ways to get it to go everywhere I needed it to go, so it held up pretty well. Once that spine breaks, it's virtually useless since the bristles start to fall out.All in all, it's an excellent product for cleaning sink overflow drains.