The Avalon single stage replacement water filter is suitable for Avalon Bottle-less Water Coolers purchased before April 1, 2018. It consists of 2 filters. An NSF certified activated carbon filter (Listed as model A4FILTER) which will eliminate chlorine, lead, or any harmful or unwanted minerals from the tap water that flows through it. The filter can be easily replaced into the cabinet of the water cooler. The filter has a capacity of 1,500 gallons of water and is made to last for 6 months of use. They have a flow rate of 0.5 gallons per minute. Your water will be tasting crisp and pure with these installed in your water cooler.