Dive masks come in two primary styles, one being a three-pane, and the other a four-pane. Both options work well but there are differences in design. For the three-pane design, the front lens is made from a single piece of material, coupled with side windows on the left and right. For the four-pane design, the front lens is made from two pieces of material and again, side windows are included. Most divers prefer the three-pane design simply because it offers better front and peripheral vision.