Potable Aqua with P.A. Plus makes drinking water safe with a two step process. These emergency water germicidal tablets are intended for emergency disinfection of drinking water. When used as directed, they make most drinking water bacteriologically suitable for drinking. Used worldwide by campers, hikers, militaries, and anyone needing to drink water of questionable bacteriological quality. Proven effective against Giardia Lamblia. For short term emergency use only. Not for continuous use. In step 1, use 1-2 tablets per liter of water to disinfect the questionable water and make it bacteriologically suitable to drink. In step 2, after using the Potable Aqua, use the P.A. Plus neutralizing tablets to remove the iodine taste and color. Each bottle contains 50 tablets.