REPLACEMENT MODELS: Compatible with Caldera Utopia 73722, Caldera 100, C-8399, FC-3965, PCD100W, 1039607. Note: All manufacturers' names and part numbers remain the property of their respective holder(s) and are used for compatibility information only. Wowreed is an independent brand. SPECIFICATIONS: Length: 16 1/2"; Outer Dimension: 8"; Top: handle; Bottom: 3 1/2" open; Filtration Area: 100 sq. ft. EASY TO CLEAN: This filter utilizes fabric structure design so as to make the impurities easy to be released and washed. It is recommended to wash the filters every 2-6 weeks in order to maximize the performance and capacity of it. In addition, our premium filter material keeps your water clearer and easier to clean. LONG LIFE: The filters are with solid end caps, good material and bands, which can be used repeatedly. Longevity and endurance are ensured. SERVICE: If there is any question, please let us know! We promise a good shopping experience with our reliable control and testing. Spa Filter Compatible with Caldera Utopia 73722, C-8399, FC-3965, PCD100W, Caldera 100,1 Pack