Premium KYNG Mask Filter! This mask replacement filter is a 40mm sealed standard filter that can directly help purify the users oxygen by productively circulating clean air through the filter. Carbon filtering is a method of filtering that uses a bed of activated carbon to remove contaminants and impurities, using chemical absorption. The filter properly operates with a peripheral sealing lip that is intended to provide protection against various agents. The replacement filter can also be connected an appropriate respirator mask air supply unit to additionally help supply clean air through the 40mm filters making it easier for the user to breath, and avoid being exposed to airborne pollutants. Filters and air supply units help the airflow when breathing in exposed air. The replacement filter can also be connected with a respirator mask hose to create a securer purification system. ***Good through at least 2030<br><br><br>