I purchased a pet water fountain on Rakuten. It came with a high-performance filter cartridge and cost 3580 yen. This is my second one, but my cat always knocks the water fountain over, so I haven't been using it. Also, the cartridges and the main unit are no longer sold on Rakuten. Therefore, although the cartridge is said to last about three months, I can't buy replacement cartridges on Rakuten. I am listing this in case anyone who uses this product would like to have it. I apologize, but I don't know about any defects as I haven't used it. Thank you for your understanding.