The Cokin Clearsky filter blocks specific wavelengths of city lights such as sodium and mercury vapor lamps. This removes the yellow and orange glow of streetlights for nighttime urban photography. It also enhances the contrast of the sky for astrophotography by darkening the gradient of the sky background and highlighting the stars or the Milky Way.Features:-Double-sided multi-AR coating and AF coating (waterproof, oil and scratch resistant) -High-resolution phosphate laser neodymium glass -Recommended operating temperatures:-10°C to +40°C -Diameter: 95 mm.