I bought my deluxe fresh flow back in 2004 when I moved to Minnesota and had hard water. I used this with bottled water and the cats loved it. When I moved and no longer had hard water, I put it away. I recently found it boxed up in the garage and plugged it in. It was a huge hit with my cats but I didn’t have any filters. I found these and they work perfectly. They don’t have the outer plastic piece the originals had, but it slide right into place and soaking for 10 minutes (to remove lose charcoal). I’ll be buying this regularly.