The rule isn't foolproof, but it should help weed out masks that aren't very protective. The Centers for Disease Control and Prevention recommends multi-layer cloth masks for the general public.

The global disposable face mask market size was valued at USD 11.38 billion in 2024 and is estimated to reach from USD 14.39 billion in 2025 to USD 94.38 billion by 2033, growing at a CAGR of 26.5% ...

Masks should fit snugly around the nose, mouth, sides of the face and under the chin, according to the Centers for Disease Control and Prevention. "The best performing masks will have two or more ...