The MyBottle Purifier from Katadyn is the only EPA-registered bottle purification system available. Simply fill the bottle with water, insert the purification system and drink from virtually any water source. It removes all viruses, bacteria, cysts from water plus the integral carbon cartridge reduces chemicals and makes water taste better. As always, each MyBottle includes a drinking straw to use as your everyday bottle if the source water is already safe to drink. Holds 24 oz. after cartridge displacement. Filters up to 26 gallons. Weighs 8 oz.