ND40B Dia. 25 mm Unmounted Reflective ND Filter; Optical Density 4.0

The ND40B is a circular Neutral Density Filter with a diameter of 25 mm and a thickness of 1 mm, sourced from the renowned optical component vendor, Thorlabs. This unmounted filter boasts an impressive Optical Density of 4.0, making it an excellent choice for applications requiring significant light reduction.

The filter is made from N-BK7 Schott glass, a high-quality material known for its excellent optical properties, including low auto-fluorescence, high damage threshold, and superior homogeneity. This ensures the filter provides reliable and consistent performance across various applications.

Both the front and back surfaces of the filter are coated with THo ND40, a specialized reflective coating that enhances the filter's performance and durability. This coating helps maintain the filter's neutrality across a wide range of wavelengths, ensuring accurate color reproduction in your optical system.

The ND40B filter features a 'Thin Lens' shape, which is designed to minimize thickness and weight while maintaining excellent optical quality. This makes it an ideal choice for applications where space and weight are critical factors.

For more information, including pricing and availability, please refer to the vendor's website using the provided weblink. The link has been verified and is currently valid, indicating that the filter is in stock.