Sediment Filter Efficiency: The Pura 36161 String-Wound Sediment Water Filter is a robust prefilter solution for fine sediment to very coarse sediment before water goes into the Pura UV20 water treatment system. High-Performance Filtration: Designed as a 5 micron water filter, this replacement pre-filter cartridge for Pura UV20 filters effectively reduces dirt and sediment in well water. Its string wound cleaner design ensures high efficiency in removing impurities from your water filter system. Long-Lasting Durability: With dimensions of 2.5 x 20 inches, this sediment water filter cartridge offers long-lasting performance and easy integration into your existing setup. This water filter cartridge replacement is ideal for maintaining optimal water filtration. The 36161 string wound water filter should be replaced every 6-12 months. Alternate Part Numbers: this water filter replacement might also be listed as Pura 33003033 or pura 26251 filter Aqua Flo, aqua flo 36161 filter This is the replacement sediment filter for the first stage in the Pura UV20 systems. It acts as a pre-filter to the carbon block and UV chamber by reducing sediment particles up to 5 microns in your water. See UV20 system manual for further installation guidance. Also known as the 36161 filter and 36161 filter aqua flo.