This spa filter cartridge is an authentic Hot Spring OEM 30 sq. ft. model (71825). It is designed to fit the Watkins Mfg. brand of hot tubs and is the perfect replacement for your old, worn-out filter. With its effective filtration system, this filter cartridge ensures that your hot tub water stays clean and clear, allowing for a relaxing and enjoyable spa experience every time. Measuring in at a unit type of feet, this filter is an essential part of any hot tub maintenance routine. Get yours today!