REPLACEMENT CARTRIDGE FOR THE KATADYN VARIO WATER FILTER: A go-to piece of backpacking camping gear, this drop-in cartridge restores your existing Vario filter to like-new performance, ready for the next section hike, weekend trip, or expedition. 500 GALLON FILTER LIFE FOR MULTI-DAY TRIPS: The replacement cartridge is rated to handle 500 gallons (1,875 liters) of trail water before needing another swap, supporting long trips and thru-hikes without mid-trail maintenance. RESTORES FRESH TASTE AND CLEAN POUR OUTPUT: Swap in a new cartridge to clear out funky off-taste and restore clean water flow. Replace once your cartridge nears its rated life or when taste and flow start to decline. TOOL-FREE DROP-IN INSTALL FOR THE KATADYN VARIO: Purpose-built replacement for the Vario filter housing - swap it out at the trailhead and keep moving. Vario filter sold separately. Katadyn Has Been Making Water Safe Since 1928: For nearly 100 years, Katadyn has delivered clean water to hikers, travelers, campers, and aid workers worldwide. At home, on the road, or in the backcountry, clean water within reach.