First Need XL Replacement Cartridge Kills or removes bacteria, viruses, giardia, cryotosporidia, parasitic cysts, pesticides, algae, odors, colors, sediment, foul tastes, herbicides & organics Purifies water in one pass without using chemicals Flow rate of 2.0 qt./min. Average canister capacity of 150 gallons. "Direct-Connect" for attachment to popular trail bottles