Amazon.com: Costa del Mar Isabela White Tortoise Blue Polarized 580 Costa Del Mar Isabela Sunglasses 365 Wholesale Costa Del Mar ISABELA Grey Polarized Polycarbonate Ladies Sunglasses IB Costa Del Mar IB 10 OGP Isabela Sunglasses TackleDirect Costa Del Mar Isabela Women's Polarized Sunglasses Tortoise Havana Costa del Mar Isabela White Tortoise Green Polarized 580 Glass Lens. The Costa sunglasses fit guide is a range from Narrow, Regular to Wide with most people choosing Regular. Fit is a combination of both the size of the sunglasses and the features of the frame, together. The features of our sunglasses influence the way the sunglasses fit, like the hinges and temple construction. Use the fit guide to select a Costa sunglass frame that will be comfortable and perform for you.