1、Optical Glass and Aluminum Alloy: Our camera ND filter features shockproof tempered optical glass and an aluminum alloy frame. This makes it long lasting and nearly unbreakable, providing dependable performance and a long service life. 2、Adjustable ND Value Design: The filter includes a combination frame that allows for adjustable ND values by rotating the frame. As you turn, the filter shifts from light to dark, offering customizable options for achieving the desired effect in various lighting conditions. 3、CPL Stacking Principle: The variable neutral density filter uses a two CPL stacking principle to achieve variable density. Its recommended operational range is ND2 to ND400. It is important to note that high density levels like ND1000 or ND2000 are beyond its capabilities. 4、Optimized Gradual Dimming: To use the filter, familiarize yourself with the scale, attach it to the lens, and observe color changes while rotating from minimum to maximum. Mark the scale position for long exposure shots, as higher densities may require more than 4 seconds to balance uneven dimming. 5、Exposure Management: Any uneven dimming is not a quality issue but rather a moire fringe effect, which can be eliminated with long exposures. The maximum position is the limit where usage approaches ND1000, indicating noticeable performance limits. Item Type: ND2 to ND400 Filter Material: Optical Glass, Aluminum Alloy 1 x ND Filter 1 x Storage Box