2. If you do not know the replacement part number for your cartridge, then use the following steps as a guide to choose the right cartridge:
a. Measure the outside diameter of the cartridge in inches (+/- 1/16)
b. Measure the overall length of the cartridge in inches (+/- 1/16), including the end caps. Do not include any handles, strings, etc.
c. If the top and/or bottom is open, measure the inside diameter of the opening (+/- 1/16 inch). If the end cap is closed make note of its identifying features (i.e. "Handle", "Cone", etc.).
3. Each cartridge with a filtration area of 145 sq. ft, 4-pack for 580 sq. ft.
The information provided about manufacturers' names and part numbers is only for compatibility and they still remain the property of the respective holder(s).