Learning the components of the scuba mask and their use will help you make the best descision. The human eye cannot focus in water, the mask provides an air pocket so your eyes can focus and you can see clearly underwater. The Skirt of the mask must seal to your face to provide this air pocket. The mask encloses your nose to allow you to equilize your air spaces during all pressure changes. Because swim goggles do not enclose the nose and have no way for you to equalize they cannot be used for Snorkeling or Scuba Diving. Always look for tempered glass, plastic fogs up and standard glass is hazardous if accidentally broken. Fit and comfort are very important to check before you choose the your mask. The skirt of the mask should wrap around your eye area with no gaps and seal from leakage. See our video on How to Properly Fit a Mask.