Hollis M-4 Scuba MaskHollis M 4 is a is low profile mask that offers superior peripheral and vertical vision. Mask has a single lens made from tempered glass for excellent optical characteristics and safety. The frameless black silicone skirt has a double feathered edge for a perfect seal, large one handed nose pocket for easy ear equalization. The easy adjust buckles and quality wide split black silicone mask strap will keep the mask properly in place The mask comes with