PROMASTER DIGITAL HD CIRCULAR POLARIZING FILTERS increase color saturation and reduce reflections. The neutral gray HD polarizing material guarantees excellent images while minimizing loss of light. Constructed with premium Schott optical glass these filters are designed to yield extreme image sharpness. They also feature a precision machined, super slim aluminum frame with anti-reflective matte finish and knurled edges. High light transmission HD polarizing material - transmits up to 25% more light than a standard polarizer Premium Schott optical glass Precision machined aluminum ring with matte finish and knurled edges Super slim 4.5mm effective profile Filter Size: 105mm