The Aqua-Pure AP811 replacement cartridge is a large-diameter cartridge ideal for larger homes and commercial applications. Although the AP811 is compatible with most conventional Aqua-Pure™ housings and whole house water filtration systems, it has been specifically designed to work with the following whole house systems: AP801 (discontinued), APWC801, AP801B, APWC801-C, AP801T-C, and AP801-1.5-C. The AP811 cartridge efficiently removes particulate impurities and contaminants from drinking water. It uses an innovative, patent-pending technology that provides a very fine filtration system, down to 25 microns. The cartridge's grooved design increases surface area for a longer filter lifespan, while the rigid construction helps to eliminate sediment "unloading" due to variances in water pressure. This design provides a 25% longer filter life when compared to similar looking water filter replacements. Product Benefits: Patent pending technology provides fine sediment filtration down to 5 micron Grooved cartridge increases surface area for longer cartridge life Rigid construction helps to eliminate sediment “unloading” due to variances in water pressure Ideal for larger (2.5 baths) homes and commercial applications