40.5mm variable ND filter with ND2–ND32 provides 5 exposure brightness stops. The ND values ND2, ND4, ND8, ND16 and ND32 indicate the fraction of light entering the lens, allowing precise control of exposure and shutter speed when shooting rivers, waterfalls, and scenes with bright light layers. No dark spots crossed. Markers on the frame allow you to rotate the filter and adjust the ND stop accurately and with ease. When mounted on a wide-angle lens, you can rely on consistent performance without dark cross spots. A 43mm lens cap is needed to fit the 40.5mm filter. Multi-layer HD optical glass nano coating. Made from high-quality Japanese AGC optical glass, the ND filter delivers a cinematic look without compromising image quality. It features 30 layers of double-sided nano coatings with a low reflectivity of 0.1%, reducing glare and ghosting while protecting the filter from moisture, oil, dust and scratches. Professional construction. The aircraft aluminum frame keeps the filter lightweight. Thickness is 0.37 inches / 9.5 mm with threads and 0.29 inches / 7.4 mm without threads, providing an ultra-thin profile to minimize vignetting. Finished in matte black and precision CNC machined for durability, it resists sticking on the lens. Use scenarios - Water features: capture rivers and waterfalls with longer shutter speeds to achieve smooth, silky water while maintaining scene detail. - Daylight landscapes: balance bright skies and contrast to retain cloud and texture without overexposure. - Creative motion: generate motion trails in urban or night scenes, such as light trails or moving clouds, with controlled exposure.