The resilient, battle-hardened CDI sunglass has a long track record of saving eyes and lives in hostile situations. The ESS CDI's U.S. MIL SPEC high-impact lenses can be easily exchanged for quick adaptation to your environment. Its high-speed low-drag frame and shatter-resistant lenses make the CDI comfortable and cool enough for downtime yet functional and rugged enough for the battlefield. Medium fit. The CDI's Lateral Exchange System makes interchanging any of the available lens colors quick and easy.