Tifosi Optics designed the Radius FC Photochromic Sunglasses for fitness freaks, road runners, and dedicated golfers. Their Fototec red lenses offer a mid-range contrast for high speed activities, and they adjust light transmission depending on the light conditions. The Radius has an interchangeable design, so you can switch out these lenses with different ones (sold separately) by Tifosi Optics. The lenses offer excellent protection against UV rays, and their ventilated design ensures optimal airflow when you work up a sweat. Tifosi constructed the Radius out of a highly durable TR-90 frame, and the ear pads are adjustable to ensure a secure fit. Hydrophilic nose pads offer a no-slip fit for extra convenience when you're mid-run.