The Water Filter Cartridges by Everpure: 4SI Water Filter Cartridge, 4SI Cartridge, (1) 4SI Fibredyne submicron cartridge, reduces particles & cysts, scale inhibitor, 15,000 gallons, 2.0 gpm, 0.5 micron, NSF 42 & 53 (EV960651) ( Everpure - EV960651 )