PSD125-2000 - Replacement Hot Tub Filter Cartridge for Sundance Spas Hot tubs and spas offer year-round enjoyment, but to ensure they remain safe and clean, proper maintenance is crucial. Filters play a key role in keeping the water clean and maintaining its chemistry. Constructed with pleated material, these filters trap debris and tiny particles, ensuring a sanitary experience. It's recommended to clean cartridge filters every 1-2 months and replace them every 4-6 months, especially with frequent use. REPLACEMENT FOR Filbur FC-2780 Unicel C-8326 Pleatco PSD125-2000 SPECIFICATIONS Diameter 8 1/2" Length 19" Top 2 3/16 " Slip Bottom 2 3/4 " beveled edge Simply reorder based on the manufacturer of your previous hot tub filter, locate a part number or measure the length and then the top and bottom diameters. Please contact us if you have any questions, we are happy to help! 1 (866) 515-MIGO (6446) Fits many Sundance Spas.