Every now and then a product comes along that changes your opinion of the manufacturer...trying to replace sink faucet cartridges with this tool changed my opinion of Moen. Why? For one, it is ridiculous that you need a special tool to change out the cartridge in my sink. Two, the design of this tool and the plastic nuts it is "supposed" to remove is poor. Moen decided to use custom plastic "nuts" to hold the cartridges in the valve body and this "tool" is supposed to be able to easily remove those nuts. On paper it sounds straightforward, in reality it is hit or miss. The "tool" is simply a piece of rolled metal. It is nothing special other than being the right size to fit in the hole and having the two "teeth" that can fit in the notches on the plastic cartridge nut. So in using the "tool" you stick it in the hole, engage the plastic notches in the plastic cartridge nut and simply twist it out. Or so they would have you believe. First, the "tool" is not the exact thickness it should be to fully seat against the notches in the cartridge nut. This means that the surface area of the teeth of this "tool" is not the same size of the surface area on the plastic notches, so when you put pressure on the "tool" to attempt to unscrew the cartridge nuts, that pressure is being applied to only a portion of the surface of the nut increasing the chances of damaging the plastic cartridge nut. Second, the tool has nothing to help hold it to increase grip and leverage to turn it. It is a smooth cylinder of metal. You need to apply both down force and turning force to use the tool. So you can clamp down on it with vise grips which will mar the surface, and produce tiny flecks of whatever metal this is made of, or try to hold onto it with a rubber grip wrench or similar. One of the other reviews mentioned the best solution, drill holes through this metal cylinder "tool" so you can stick a screwdriver through it and make it into a T-handle tool. This is highly recommended as using the "tool" the other way will only increase the chances of the second major issue with using this "tool" (destroying the plastic cartridge nut). How hard would it have been for Moen to add these holes? Pretty easy, no idea why they did not. Cheapness? So once you get past the design of the "tool" itself, does it work? Maybe. I have found with using this tool that it is very hit or miss and only works about 50% of the time. The reason is simple, the cartridge nuts can be "stuck" in the valve body from years of being in place and possible corrosion from leaks. The force required to remove these "stuck" nuts can exceed the strength of the plastic retainer nut. So in the cases where the valve has been leaking, the exact case in which you would want to use this "tool" to replace the cartridge, odds are high that this "tool" will damage the plastic cartridge nut instead of easily removing it. For a faucet valve that has not been leaking, such that the valve body is not corroded, I found this "tool" works ok. So let's review, for a faucet valve in good condition and probably not leaking, so really does not need to have the cartridge replaced to start with, this tool will probably work. For a faucet valve that has been leaking, or has been in place for many years, this "tool" has about a 50% chance of destroying the plastic cartridge nut you so desperately need to remove using this tool. Unfortunately, there does not appear to be many options. So if you are indeed dead set on trying to replace your leaking faucet cartridge on your Moen faucet, you will need this poorly design tool, just know that your chances of success are probably 50/50. I spent many hours working with this trying to repair one leaking faucet cartridge, and I destroyed two plastic cartridge nuts in the process. You can't buy the plastic nuts by themselves, they come in a parts "pack" so you are looking at the cost of this tool plus about another $12 to buy replacement nuts. If the tool does not produce the positive result, you will be further looking at hours of frustration. One of the other reviewers mentioned the best solution was to remove the faucet, throw it away, and buy another. If you get this "tool" and try it, and it destroys the plastic cartridge nut, I would recommend the replacing the faucet approach as well unless you are really attached to that faucet. My builder had coordinating faucets, towel bars, and toilet paper holders so I really needed to make this work, plus Moen does not make my faucet series (Asceri) anymore. However, in my darkest hours of frustration staring at a mangle plastic cartridge nut, I still went online and looked at replacement faucet choices. :(
