And you may be curious about the red-glowing masks that you’ve seen making the rounds on social media. Red-light masks use low levels of light-emitting diode, or LED, to stimulate skin cells, says Dr.

P95 and N95 are rating classifiers for masks manufactured to keep people from inhaling dust and other small particles in unsafe environments.

We tested six sleep masks to compare their overall comfort and ability to deliver total darkness during sleep. There’s just one we recommend buying.