A bit expensive, just foam that fits around the water pump on a Drinkwell fountain

The foam smelled very highly of a chemical, and although I rinsed them very well beforehand, when I placed them in the fountain it gave the water a chemically and chlorine smell

But come on, $3 for each piece of cheap foam?

uneven foams in some boxes!!!

I will always keep a good foam filter in the cat's water from now on.

Works as it should.

They come 2 per pack and work as they are intended to.