Dive into pristine waters with the Hurricane HF4H21-01 Advanced Cartridge Filter, where unparalleled cleanliness awaits. Crafted with meticulous precision, this filter guarantees seamless compatibility with Unicel 4CH-21, Pleatco PTL18P4, Filbur FC-0136, and other compatible models. With dimensions measuring 8 inches in length, an outer diameter of 4.63 inches, a top handle, and a bottom hole of 1.5 inches, achieving an ideal fit is effortless, measure your current filter for a flawless match. Experience a new level of filtration prowess with the advanced point bond filter media of this spa essential, elevating filtration effectiveness beyond traditional non-woven materials. From biomass to dirt, debris, hair, leaves, and even critters, this pool filter is a formidable barrier, leaving your pool or spa immaculate and inviting. Esteemed by both industry professionals and homeowners, this spa accessory is meticulously engineered for durability, ensuring prolonged service life and effortless upkeep. Bid farewell to the inconvenience of frequent replacements and welcome substantial savings on filters, all while minimizing wear and tear on your pump. Discover the exceptional cleaning prowess of the Hurricane HF4H21-01 Advanced Cartridge Filter, your ultimate solution for pristine waters and unparalleled excellence.