These cartridges are suitable for the following products:

SK422 Butterfly Pet Fountain

SK4231 Drinkwell Pet Fountain 1.8L

SK4232 Drinkwell Pet Fountain 3.7 L

SK4233 Drinkwell Pet Fountain 7.5 L

SK424 Streamside Ceramic Pet Fountain 1.8L

SK425 Seaside Stainless Steel Pet Fountain 1.8L