Product Description This is a professional-grade reverse graduated ND filter made by Singh-Ray. Features: Size: 100x150mm (4x6 inches) ND-3 (0.9 density) = 3 stops reduction Special design with density changing from the center to the edges Ideal for sunrise and sunset photography Made of CR-39 optical resin Compatible with Cokin Z-Pro and LEE systems Product Condition: Near new This special filter is favored by professional landscape photographers. It enables shooting in situations where the sun is in the center of the frame, which is difficult with regular graduated filters.