Costa Mainsail Polarized Sunglasses - For the performance and style you need on and off the water, our Mainsail frames are your go-to pair for every outing and adventure. Built with the same high-quality materials and features you want everywhere from the beach to the big blue, Mainsail frames help keep excess light out with micro side shields and hooding, your frames in place with improved Hydrolite grips on the temples and help keep sweat and water out of your eyes with eyewire drains and channels.The Mainsail frames are your day-to-day sunglasses that stay stylish while relaxed on land and ready for anything while out on water. Costa 580 lenses were designed by in-house light spectrum experts to enhance colors because standard sunglass lenses fell short. The lens' multipatented technology manages light by: Absorbing Harmful High-Energy Blue Light (HEV) Enhancing Reds, Greens, and Blues Filtering Out Harsh Yellow