Faraday Defense hand-crafted the Copper Shield Liner to give your mask the protection you need from harmful viruses and bacteria entering your body. Copper has been proven to destroy microbes within a few hours of contact. It was also designated as antimicrobial by the U.S. EPA (Environmental Protection Agency). Our 100% copper liners are antimicrobial, antibacterial, and hydrophobic. The liners are also very lightweight and breathable, allowing healthy airflow. Simply slip the Copper Shield Liner into the filter pocket of your mask and experience ultimate protection! \n \nThe Copper Shield Liners may be used with any mask containing a filter pocket, however, for an exceptional fit, use with the Faraday Copper Shield Mask. For best results, do not wash the liner. Note: Copper may oxidize over time. \n \n Made of 100% Copper \n Antimicrobial, antibacterial and hydrophobic \n Inserts into filter pocket of mask \n Lightweight and breathable \n Sold in packs of 2 or 5 liners \n