Aquamira GRN Series IV Filter 67020Frontier Replacement Filter. Hi Flow bacteria filter provides ultimate protection from bacteria, Cryptosporidium and Giardia with up to 800 ml minute flow rate. Designed for use with the Frontier Max Filtration System (67018). Reusable filter tube protects the filter during storage and transport and can be repurposed to hold small items. Miraguard Antimicrobial technology suppresses the growth of bacteria, algae, fungus, mold, and mildew within the