509 Sinister X5 Replacement MaxVent Lens - Chrome Mirror/Yellow Tint The 509 MAXVENT has 6 large top vents and two strategically placed lower lens vents. Perfect for riders that need increased airflow for improved anti-fog performance. Dual lens technology, designed specifically for cold weather & high moisture use. Featuring complete UV protection, dual lens panes, anti fog, anti scratch, and shatter proof. This dual view technology is a new feature 509 perfected & included on many 509 goggles, so they not only look sharp when in action, but also have the unique functionality of two completely different views depending on if you are the one using the goggles or viewing them from the outside. Fits: 509 Sinister X5 Goggles