They come in all different styles and colors, but researchers at Duke University have some advice for which masks to wear and which ones to avoid.
They say neck gaiters or fleece masks worn around the neck and pulled up over the mouth and nose are counterproductive and might actually spread COVID-19 instead of stopping it.
That's because they found when someone speaks through a neck gaiter, it broke the larger droplets up into smaller ones, which can stay in the air longer.
Researchers discovered that out of 14 commonly used masks, gaiters were the least effective.
They also recommend avoiding bandanas because, although they may look cool, they do not work well.
Previous studies have found these types of masks are less effective, but this was the first to show it is possibly more dangerous than no mask at all.
Looking at other masks tested by the group, medical-grade N-95 masks trapped droplets the best. But those should be reserved fr frontline workers who need them most.
The standard blue surgical masks you can find at local stores were the next best option, and cotton masks with several layers of cloth also did well, releasing less than 0.5% of droplets.
In the meantime, the Centers for Disease Control and Prevention warns people to avoid masks with vents or valves.
It says they are not as effective in preventing the spread of COVID-19 because air and droplets can escape through the holes, reach others and possibly infect them.