When you are out there snorkeling, you'll see that guy in the water who keeps stopping to take off his mask?

The reason is because no one showed that snorkeler how to choose his snorkeling mask properly.

After reading this webpage content, you will know what to look for in a snorkeling mask.  

Most Important Thing to Look for in a Snorkeling Mask
How to Find a Mask That Fits You
Other consideration when choosing a Snorkeling Mask
Top 3 Ways to Keep Your Mask From Fogging