Generally speaking...
Face masks protect OTHERS.
N95 respirators protect YOU.

Flu viruses usually enter through your nose, mouth, or eyes. An N95 respirator helps block the viruses by filtering very small particles - including germs - from the air you breathe. Wear an N95 respirator whenever you are caring for a sick person or are otherwise exposed to people who have the flu.

Tip:  Some N95 respirators have a one-way valve/vent for easier exhaling & to reduce heat build-up. The circular valve is in the center of the respirator "mask."

Some of the product listings are for a single or 2-pack of respirators while other listings are for boxes or cases of 10, 20 or more respirators. N95 respirators are intended for one-time use, then disposal (because flu viruses may be on the outside of the respirator). So, buy an adequate supply.

Also consider buying extra to share with family, friends, or neighbors who may have lacked the foresight to buy a supply.