The Chemix™ gravity block is designed to provide high-quality drinking water for pour through and gravity type systemsfor municipally treated water supplies. This molded block technology is designed to reduce particulate, chlorine, VOC’s,lead, and mercury without pressure, and without priming or pre-wetting procedures. Specifications Chemix® silver impregnated gravity block is specifically designed for gravity and pour through filter systems. Reduces chlorine, lead, mercury, and VOC’s. Designed to fit all AquaCera® gravity filter systems. Does not require priming 1 Gallon per hour performance One gallon per hour performanceNo priming, or pre-wetting of the filter required>95% Lead and mercury reduction>95% VOC reduction (includes 62 compounds)>95% Chlorine reduction