Sagan UltraFlo Universal Water Filter 10in. The patented filtration media technology used in all Sagan water purification products is based on electroadsorption of contaminants not mechanical filtration. The electro-positively charged media acts like a magnet attracting and retaining contaminants as small as viruses out of the water as they come in contact with the media. The media itself is made of layers of non-woven nano-alumina coated glass fibers containing powdered activated carbon (PAC) and antimicrobial protection (silver). The positively charged media field is sandwiched between layers of spunbond polyester which provides strength to the pleated media. The proprietary filter media offers exceptionally high flow rates and efficiency in removing contaminants. The media has been shown to remove viruses bacteria cysts volatile organic compounds (VOCs) disinfection by-products endotoxin natural organic matter and other sub-micron particles and therefore making it IMPOSSIBLE FOR DANGEROUS ORGANISMS TO PASS THROUGH. Changing your filter will depend on how much water you use and how contaminated it is. Since the filter acts as a magnet as mentioned above your filter will get clogged up over time. When it gets to the point of not being able to get water out of the filter or the flow is not sufficient for your needs it is time to change your filter. Even if there is only a trickle of water coming out that water is still safe to drink. Specifications for Sagan UltraFlo 10in Universal Water Filter: Manufacturer: Sagan Size: 10 in Age Group: Adults Weight: 6.2 oz Package Contents: Sagan UltraFlo 10in Universal Water Filter Sagan 57215: UltraFlo Universal Water Filter 10in