I'm selling these because the size didn't fit and I couldn't use them. They come in a pack of 3, but I've opened one, so I'm selling the remaining 2. If you'd like, I can include the third one as well, even though it's been opened. It's unused. These are replacement cartridges for built-in filters, compatible with the removal of 17+2 substances. - Model Name: TJS-TC-S19 - Quantity: 3 cartridges - Filter Type: Built-in type - Substances Removed: 17+2