This splash guard holder is the part that the mister sits in, and it also supports the glass splash guard. It is compatible with all of the mist makers we sell because it has the largest inside dimensions. Some of the smaller misters may be slightly looser inside of it, but they will all work quite well. The ML-21 fits perfectly inside this holder, and it is the only one big enough to surround it. If you have a mister that is smaller than the ML-21, then you can check out the other holders we carry, as one of those may be more to your liking. For other holder options see: Splash Guard Holder A and Splash Guard Holder C. If you are building your own humidifier or fountain, this will be the part that the holds the mist maker, and supports the splash guard. It is quite necessary for indoor applications, because as the mist is made, there will always be some splashing. When this part supports the glass dome over the mister, it will serve to block the larger splashes, and keep the area outside the bowl dry and mess free. Because it has just a single vertical support, it will not hold back any mist, and all of it will flow freely. Even if your holder that you are replacing does not look like this one, you can still use it with great success, just so long as your mister fits inside. Take a look at the specs to view accurate dimensions so that you can determine compatibility. These risers are designed to last for years, but due to accidents, loss, or other factors, you may need to get a new one. This one is a good choice for almost anyone due to the larger size and easy ability to direct the cord where you want it.