【 NSF/ANSI 50 CERTIFIED QUALITY】POOLPURE Spa filters are rigorously tested and certified by IAPMO to meet the NSF/ANSI 50 standard, ensuring dependable performance and crystal-clear water quality for your spa. 【SPECIFICATIONS】Length: 6 5/8", Outer Dimension: 4 5/8", Top: 2 1/8" open, Bottom: 1 1/2" MPT Thread open. Filtration Area: 25 Sq.ft; Filter Material: Trilobal Filtration Fabric. 【COMPATIBLE MODELS】 PLF4CH-22 Spa Filter is compatible with PFF25P4, Freeflow Lagas FF-150 TLX RLX, Unicel 4CH-22, Filbur FC-2399, Aladdin 12535, Baleen AK-90031, Excel Filters XLS-443, Pure N Clean PC-2399, Tier1 PAS-1244, SD-00205. ★NOTE: POOLPURE is an independent brand offering compatible replacement products that are engineered to meet OEM standards. All original manufacturer names and part numbers are for reference only. 【SUPERIOR FILTRATION PERFORMANCE】The advanced "Dirt-Locking" technology captures over three times more debris than standard filter cartridges, including hair, dust, fine particles, and sediment, ensuring consistently clean, fresh, and crystal-clear pool or spa water. 【EFFORTLESS CLEANING】The filter's trilobal fabric structure allows impurities to be released easily during cleaning, keeping the cartridge feeling like new. For optimal performance, clean once a month. ⚠️ Do not backwash — backwashing may cause cracks or permanent damage.  POOLPURE Spa Filter Replaces Unicel 4ch-22 Freeflow Lagas FF-150 CLX TLX, PFF25P4, Filbur FC-2399 Filter Cartridge, 1-Pack