The CDC recently warned masks with valves can cause droplets to escape into air, through a hole where the vent is located. This speaks to using N95 masks, NOT the single vented masks sold at TCB!! Our single vent masks have the vent attached to the outer layer, leaving the inner 2 layers of cotton material intact, as the CDC recommends. Additionally, using the included filter adds an extra 5 layers of protection between you and anything beyond the mask!