Black Berkey® Purification Elements are more powerful than any other gravity filter element currently available.The powerful Black Berkey® purification elements removes or reduce pathogenic cysts, parasites, harmful or unwanted chemicals such as herbicides and pesticides, VOCs, detergents, organic solvents, trihalomethanes, cloudiness, silt, sediment, nitrates, nitrites, heavy metals, foul tastes and odors.