The MSR TrailShot / Trail Base Water Filter Replacement Cartridge is a replacement cartridge for the MSR TrailShot Microfilter and the MSR Trail Base Gravity Filter. Effective against bacteria (99.9999%), protozoa (99.9%) and particulate, this cartridge filters up to 2,000 liters without iodine, chlorine or other chemicals. Its hollow fiber technology allows water to pass through but traps harmful protozoa, like giardia and cryptosporidium, and bacteria, like salmonella. Ultralight (1 ounce) and compact (3x1 inches), so it is easy to fit an extra replacement cartridge in a backpack for backcountry and camping adventures. Cartridge refreshes the flow rate, and filters 2,000 liters before needing to be replaced. Manufacturer's 3-year limited warranty.