More than ever, it’s important to wear a face mask whenever you plan on being in public. But while any mask is better than not wearing one at all, not all masks are created equal. The most effective masks are N95s. N95s are personal protective equipment that have been certified by the FDA to block at least 95% of very small particles, about 0.3 microns. The CDC does not recommend N95s for the general public, as these are vital supplies that should be reserved for medical workers. Homemade face masks or DIY face masks made from cotton are more common. These are effective to a point—they will block bodily fluids that carry the virus. But homemade face masks do not filter particles out of the air. Pathogens can still reach you through the mask. Melt-blown face masks are much more effective. An outer layer repels fluids to protect you from infection, while an inner layer absorbs any moisture you exhale to prevent you from infecting others. The most important layer, however, is the one inside. This layer is made from melt-blown fabric. While woven fabrics can allow tiny particles to pass through, the melt-blown manufacturing process converts polymers directly into extremely small fibers capable of filtering out pathogens. This melt-blown layer is the part of the mask that stops the virus in its tracks. If you’re planning on going to a public place, it’s better to wear any mask than none at all, but wherever possible, wear a 3-layer mask with a melt-blown inner layer to protect yourself and your family.