Use these to increase contrast in some images, especially in daytime photography. You can also reduce the brightness of an object, usually the Moon or a planet in order to enhance the ability to see fine details. Also helpful for splitting binary stars by reducing glare and diffraction around the brighter star of the binary pair.
Retains true color balance since all wavelengths are transmitted uniformly over the entire spectrum. Has a standard 1.25" male filter thread (M28.5x0.6) on one side and a female thread on the other side, so you can stack this filter with other 1.25" filters. In fact, you can combine two of these filters together to create a variable polarizing filter at a significant discount to buying a dedicated variable polarizing filter separately.
Comes in a protective plastic storage box. Made by GSO in Taiwan.