The 3M 5618904 Whole House Large Diameter Replacement Water Filter Drop-In Cartridge is a replacement water filter cartridge for the AP801 and AP802 whole house water filters. This cartridge is a drop-in replacement and has a large diameter, making it suitable for larger water filters. The 3M 5618904 Whole House Large Diameter Replacement Water Filter Drop-In Cartridge is made of durable materials and is designed to provide optimal water filtration performance for your home. The 3M 5618904 Whole House Large Diameter Replacement Water Filter Drop-In Cartridge is a replacement water filter cartridge for the AP801 and AP802 whole house water filters. This cartridge is a drop-in replacement and has a large diameter, making it suitable for larger water filters. The 3M 5618904 Whole House Large Diameter Replacement Water Filter Drop-In Cartridge is made of durable materials and is designed to provide optimal water filtration performance for your home.