This product has been discontinued by the manufacturer. Please follow this link http://www.filtersfast.com/Aqua-Pure-Water-Filters-cat.asp to find a suitable replacement.
The Aqua Pure RO3RC Replacement Filter Kit includes all the replacement filters for the APRO3 Reverse Osmosis System, except for the membrane. Includes two AP397E-3 Carbon Filters, and one AP390E Sediment Pre-Filter. Also known as part 6850801, 68508-01.
The R03RC filters should be replaced every 6 months for optimum performance.