The I/O MAG, utilizing the Smith MAG interchangeable system, is designed for optimized performance and perfected fit: two locking mechanisms for lens security, AirEvac ventilation for fog-free integration with Smith helmets, and a frame designed for contoured face fit. All this technology is designed around one of Smith's largest spherical lenses, providing a maximized field of view and 5X anti-fog technology. The I/O MAG was designed through a process of reducing elements to only the most essential, so there's nothing getting in the way of a great day on the mountain. Smith MAG interchangeable system Includes bright light and low light ChromaPop performance lenses Spherical carbonic-x lens 5X anti-fog inner lens TLT lens technology for crystal clear vision