With omicron sweeping the nation, health officials are recommending that Americans upgrade their face masks to provide sufficient protection against the highly contagious virus. Their suggestion is to opt for a tight-fitting medical-grade mask such as the N95, KN95 or KF94 masks that filter out 95% of airborne particles, according to the Centers for Disease and Prevention (CDC).

The difference in these recommended masks boils down to their country of origin or the organization that certifies the mask, says Forbes. The N95 masks made in America are certified by the U.S. National Institute of Occupational Safety and Health (NIOSH). The KN95 masks are made in China and meet Chinese standards, while the KF94 masks are manufactured in Korea and meet that country’s requirements. While meant to be disposable, if needed these masks can be reused as long as there are no blood or nasal secretions on them, and the nose piece and straps are not broken, says the CDC.

According to a study published in the Journal of Emergency Medicine, to sanitize these masks researchers suggest numbering the masks from 1 to 4 and rotating them every three days in numerical order. “All SARS-CoV-2 viruses on the mask will be dead in 3 days,” write the authors of the study. “Masks should be kept at room temperature.” To store masks between wearing, keep them in paper bags.

“An N95 is the best, if you can get it,” said Dr. Bob Lahita, director of the Institute for Autoimmune and Rheumatic Disease at St. Joseph’s Health and author of the upcoming book Immunity Strong. “But they’re hard to get — the good ones are hard to find.”

You can find resources on where to buy the best N95s, KN95s, and surgical masks here. The masks were evaluated by government experts in collaboration with Colorado State University for their protection, legitimacy, fit and feel as well as their value. But even these masks won’t be effective if they do not fit securely, according to CNET. Make sure the mask fits snugly, without any gaps around the nose, face, and mouth.

If you can’t find the preferred masks easily, double mask, say experts, wearing a surgical mask with a cloth mask on top, but don’t wear a cloth mask alone.

“Cloth masks are little more than facial decorations,” Dr. Leana Wen, visiting professor of health policy and management at the George Washington University Milken Institute School of Public Health told CNN Newsroom. “We need to be wearing at least a three-ply surgical mask. You can wear a cloth mask on top of that, do not just wear a cloth mask alone.”

As the U.S. reports a seven-day average of 668,407 new cases of COVID-19, we are facing the highest level of cases ever reported during the pandemic, says Forbes, and hospitalizations are also on the rise. Upgrading your face mask, getting vaccinated and boosted and observing social distancing are crucial steps to protect against omicron.