If you are thinking of the one paned mask you last saw Sean Connery wear in a Bond movie think again. Scuba diving masks have evolved to offer a range of styles and fit to suit different faces. A mask creates an air pocket in front of your eyes for easy focus while the nose pockets help you to regulate air pressure as you dive; hence a mask should offer an airtight fit. There are many designs and varied pane styles to choose from. Do a seal test before choosing your mask.