The Smith 4D MAG S offers advancements in technology from the original 4D MAG in a slightly smaller frame for smaller faces. The introduction of BirdsEye Vision increases the overall field of view by 25% compared to the other I/O MAG models. This increase in field of view offers unparalleled, unobstructed vision all day long. The 4D MAG S also comes with an upgraded interchangeable lens system. In this goggle the magnetic locking mechanisms are integrated into the frame’s outriggers. This makes changing lenses quicker and easier than ever before. Smith definitely brings the the on-mountain optic game to a whole new level with this all-new 4D MAG S goggle.