2-PACK pH Replacement Filters for Seychelle pH2O 28oz Water Bottle. Dual-chambered filter pH20 with Alkaline pH Enhancing Filter AND Radiological Filter - pH2O Pure 2-PACK of Manufacturer's OEM Replacement Filters for the pH2O Pure Water Bottle by Seychelle Increases the alkalinity (pH) of drinking water up to 9.5 pH with proven tested technology. Made in the U.S.A. Removes up to 99.99% of toxic chemicals, contaminants, and pollutants. See list in product description below. Can also be used with ANY 28oz Seychelle bottle (Extreme, Advanced, Standard, Radiological), the 38/42oz. canteens AND the water pump (version 1). Completely interchangeable. Filters radiation including Radioactive Iodine I-131 from a nuclear reactor or nuclear weapon. See full list below.