Cat water fountain filters, set of 9 (unused) I mistakenly purchased the wrong size and they don't fit my water fountain, so I'm selling them. This is a set of 10, and I only used one. The remaining 9 are unused. The box has been opened, but the contents are in good condition. *Please confirm compatibility with your water fountain model before purchasing. *Please refrain from purchasing if you are sensitive to items stored at home. Instant purchase is OK. Thank you.