A new study at Duke University looked at 14 different types of face coverings to see which ones block the most particles. And there were some clear winners and losers. Overall, they found N95 masks work best and block the most particles. Which isn’t surprising. Disposable surgical masks were almost as good though. And homemade cotton masks with multiple layers did well too. They all offered good protection. Knitted masks with bigger holes like a scarf didn’t block as many particles, for obvious reasons. And bandanas didn’t do well either, partly because they’re single-layer. But the worst mask by far were NECK FLEECES, also called gaiter masks. They’re the ones you wear around your neck, and a lot of people use them when they work out. They didn’t block a lot of particles though, and might actually make things WORSE. The study found they broke saliva particles up into even smaller droplets that got through. And smaller droplets can float around in the air longer, so they’re more likely to get someone sick.