The label on the right side with the bar code tells which filter you have. It should say
P/N 160310 (CCP240)
P/N 160340 (CCP320)
P/N 160301 (CCP420) or
P/N 160332 (CCP520).
The length of the cartridge will also tell you which ones you need.
There are 4 different size cartridges, 60, 80 105 and 130 square feet. Four cartridges equals 240, 320, 420 or 520 total square ft.
The cartridge length should be 14, 20, 26 or 32 inches long.
R173572 Cartridge Element, 240 C&C Plus.
R173573 Cartridge Element, 320 C&C Plus.
R173576 Cartridge Element, 420 C&C Plus.
R173578 Cartridge element, 520 C&C Plus.