More information about masks and how masks protect you is available on the CDC website.
Face Covering Guidelines
All face coverings must, at a minimum:
Fit properly and closely on the face without any gaps along the edges or around the nose, fully covering your nose and mouth, and secure under your chin.
Not Permitted:
Face coverings with exhalation valves
Face coverings, including bandanas, that are unable to be secured under your chin
Neck Gaitors
Mesh materials
Face coverings which contain holes or are significantly damaged
Note: Exceptions to wearing masks apply to people who are at a restaurant or other establishment that offers food or beverage services, while they are actively eating or drinking.