Oceanic's Ion 4 mask has all the same great features of their Ion 2 mask includes a 100% hypoallergenic liquid silicone skirt, lightweight frame and low profile but adds side windows for increased peripheral vision. The Ion 4 comes standard with a neoprene comfort strap which virtually eliminates hair tangling caused by conventional silicone or rubber mask straps. The Ion 4 has easy adjusting buckles for convenience and has tempered glass lens for safety.