From day one, Oakley's goal with Flak Jacket was to create world-class sports equipment. Training and competition can take you from bright sun to overcast skies and everything in-between, they engineered an interchangeable lens design that lets you adapt. With extra lens sets, you'll always have the best optics for current conditions, and you'll be ready for whatever the sun does ten minutes from now. Important Note: Use care when installing/removing accessory lenses. Scratched lenses can not be returned and are not covered under Oakley's warranty policy.Lens SpecificationsGray: Light Transmission- 18%, Light Conditions- Bright, Contrast- Neutral, Base Lens Color- GrayFire Iridium: Light Transmission- 16%, Light Conditions- Bright, Contrast- Increased, Base Lens Color- OrangeVR28 Black Iridium: Light Transmission- 14%, Light Conditions- Bright, Contrast- Increased, Base Lens Color- BronzeBlack Iridium: Light Transmission- 10%, Light Conditions- Bright, Contrast- Neutral, Base ...