The Baader polarizing filter 2" polarizing filters are most commonly used to reduce the brightness of the Moon and planets.By twisting 2 of them together and rotating them on top of each other, you can adjust the transmittance between about 2%-40%.
The advantage of this solution is that you can always adjust the amount of light reduction conveniently, depending on the magnification or moon phase you are using. This means that, unlike with fixed aperture moon filters, there is no risk of the image being too bright or too dim. The Baader Polarizing Filter 2" has a particularly precise surface finish and anti-reflection coatings to minimize image degradation.
TIP: The most convenient way to use a pair of polarizing filters is to screw one onto the filter thread of the 2" eyepiece and the other onto the filter thread of the 2" eyepiece. Then you only need to rotate the eyepiece to achieve the desired light transmission.
Please note that the product consists of only one filter, two filters are required for the light reduction effect!