Kinda just does what you expect it do. It's cheap enough that even if it breaks it's not a big deal. Two small notes, the top part is a disc not a marble but still has a shape that's very easy to hold. Also, depending on how much you're shaking your piece while cleaning there may be a small amount of pressure holding it place, not a big deal but I was a little surprised by how much of a seal it was able to develop.

All in all, it's great, glad I bought it and very well might buy one or two more.