Sundance MicroClean Filter Ultra Outer Filter Only #6473-165 This is the OUTER FILTER ONLY. Doesn't include Sundance 6473-164 inner filter cartridge. Again this doesn't include the inner filter cartridge. You'll have to buy the inner cartridge as well for a proper fitting in the spa. Works with: 880 Series year 2009 + Works with: 850 and 880 Series years 2005-2008 Fits all Sundance Maxxus 2009 +, Optima 2009 +, Cameo 2009+, Majesta 2009 +, Altamar 2009 +, Marin 2009 + and Capri 2009+.