Neutral Density filter: Also known as neutral density filter, are used to filter light. This filtering effect is non selective,the Neutral Density filter's ability to reduce light of various wavelengths is equal and uniform. Adjustable Neutral Density filter: Rotating ring between ND2-400 giving great versatility in changing light. Reduces the amount of light without affecting colour balance. Features: Allows the use of slow shutter speeds on high speed films or digital cameras to record movement/image blur in waterfalls, clouds or any fast moving subject. Slim rim design preventing wide angle vignetting. Functon: Eliminates overly bright & faded images. Enables slow shutter speeds to record movement in subjects such as waterfalls providing a silky smooth effect to flowing water. Material: Neutral Density Filter is made of Optical Glasses + aviation aluminum frame for durability. Specification: Type: Adjustable Neutral Density Filter/Neutral Density filter Shape: Round Model Number: ND2 to ND400 Color: black Material: aviation aluminum frame Lens material: optical glass (1) Neutral Density 2: It can reduce the 1 stop aperture and 50% of the light quantity; (2) Neutral Density 4: Can reduce 2 stops of aperture and 75% of the amount of light; (3) Neutral Density 8: Can reduce 3 stops of aperture and 87.5% of the amount of light; (4) Neutral Density 400: It can reduce the amount of light of 9 stop aperture, suitable for long term exposure during the day and shooting the sun. Package Includes: 1 Piece Neutral Density Filter 1 Piece Plastic Box Note: Note: This Neutral Density mirror is suitable for long exposure in low light environment, not suitable for strong light environment, only ND2-64 can be used during the day, and above 64 is only suitable for use when the light is dark at night!