Please note this product might take a little longer to arrive as it may be shipped from outside the uk. Replacement filter for cat mate drinking fountains available in sets of 2 and 6 litres suitable for the 6 litre and 2 litre cat mate fountain models drinking fountain, ideal for cats and dogs please note when used with only one cat dog, we recommend replacing the filter monthly. When used with two or more pets, more frequent replacement may be necessary as the filter could become clogged and this could lead to premature pump failure. Note when used for multiple pets, we recommend replacing the top baffle with an additional filter element sold separately to extend the filter change intervals.