CIPA"s Safety Rearview Marine Mirror features a fully adjustable anti-scratch, quick mount plastic bracket that fits round or square windshields from 0.625 of an inch to 1 inch thick. The mirror head measures 4.25 x 8 inches. It can mount above or below the windshield. The Safety Rearview Marine Mirror features a convex acrylic safety lens for wide angle viewing and added safety. Made with non-corrosive materials and salt spray tested.