Book excerpt: Before the pandemic pandemic caused by corona virus, everyone panicked and went to buy masks to prevent influenza virus. And the first question that comes to our minds may be, "What kinds of masks are there? Which ones are effective in preventing the spread of flu viruses?" I see too many people who have yet to receive this knowledge. It's basic but essential at the moment - the world is coping with the most terrible epidemic ever. Therefore, I am writing this booklet with the desire to share the following 3 core things: 1. Can face mask prevent the spread of flu virus? 2. What types of masks are popular on the market? And benefits - the value of each type in preventing influenza spread? 3. How to use a mask properly to prevent the spread of influenza. I hope that this booklet will help you to gain knowledge about a flu mask so that you can make the right choices. And know how to wear a mask to protect yourself and your loved ones. Thanks! Dr. Timothy Z. Email: [email protected]