COMPATIBLE REPLACEMENT FOR: Whirlpool WHKF-GD25BB INCLUDES O-RING: O-ring is compatible replacement for WHKF-C9 and will only fit Whirlpool WHKF-DWHBB WHOLE HOUSE FILTRATION - 5 Micron whole house water filter with dirt sediment and rust filtration SUPERIOR FILTRATION - Raised Groove polypropylene construction provides extra surface area for more filtration and extended filter life. The plastic end caps ensure a positive seal MADE IN TAIWAN - with Standard 61 approved materials 20 GALLON PER MINUTE FLOW RATE - ideal for "point of entry" installation Compatible Filter with AP801 Compatible Oring - 5 Micron Replacement Cartridge - 4 1/2 X 9 7/8 Inch - by KleenWater. The KleenWater brand KW810EC water filter replacement cartridge is a high quality, low cost alternative to the AP810. The rigid polypropylene construction effectively removes dirt and sediment with impressive flow rates of up to 20 gallons per minute. Each cartridge contains two distinct micron layers. Larger particles are trapped near the exterior and progressively finer particles towards the filter core. Thus the cartridge has exceptional solids-holding capacity and will perform longer. The KleenWater KW810EC features plastic end caps with gaskets and a raised ridge grooved design which provides a significant increase in surface area. This replacement cartridge is an ideal choice for the value conscious consumer. The cartridge should be changed every 6 - 12 months or upon noticeable pressure reduction. 5 Micron gradient density melt blown polypropylene construction. To provide perspective to the 5 micron sediment entrapment rating it is important to note the naked human eye can see down to 20 micron and a human hair is 100 microns in diameter. The industry universal dimension of 4.5 inch x 10 inch makes it compatible with filter housing manufacturers such as GE, Culligan, Cuno, Omni, Kenmore, Whirlpool WHKF-DWHBB and Ametek "Big Blue". The smaller the micron rating the better the entrapment capability. Shrink Wrapped for Purity. KleenWater is trademark of Pavel Water Filtration. Included is an o ring that is compatible with the AP801 water filter housing. We recommend having an extra o ring on hand to avoid an urgent situation. The o-ring is constructed of Buna nitrile rubber. This material is safe and extremely effective creating a water tight seal between filter had and filter sump.