Fluoride can occur in drinking water naturally as a result of the geological composition of soils and bedrock. Additional fluoride enters drinking water in discharge from fertilizer or aluminum factories, fluoridated dental products, as well as the voluntary addition of fluoride to drinking water. The EPA has set the level of protection for fluoride at 4.0 mg/L or 4.0 ppm, to prevent potential health risk. Aries Fluoride Reduction cartridges utilize the advanced media technology of ResinTech® SIR-900 media, a synthetic aluminum oxide that remove fluoride by a chemical reaction with the media. ResinTech® SIR-900 has minimal shrinkage /swelling and low-pressure loss, and can be used over a wide pH range. Sized to fit standard Slim and BB housings.