The Pet Life ® 'Auto-Myst' 2-in-1 Filtered Water Dispenser and Food Bowl Replacement Filters are sold as a 6 Pack and designed for use and placement inside the 'Auto-Myst' Snail Shaped Food and Water Feeder. Each Filtration unit is designed to be replaced every 30 to 45 days for up to 270 Days of total usage. Designed to remove impurities in water and assist in the removal of Chemicals, Heavy Metals and Bacteria found in un-filtered water.