Baader Double Polarizing Filter
Screws into 1¼ or 2" eyepieces/threads. The two filters can be rotated relative to each other to variably adjust the brightness level for lunar observations. The Baader Double Polarizing Filter can also be used for solar observations in combination with an objective sun filter made from Astro Solar Film.
The double polarizing filters in 1¼ or 2" can not be separated into two parts, so you can't take one half as a single filter e.g. for a Herschel wedge. The reason for this is stability and quality: If both housings could be separated, they may move or be tilted to each other, which could harm the image quality and cause reflections.
Important Information for Observing the Sun
Polarizer and neutral density filters need additional filtering ahead of the scope or eyepiece for any observing of the sun (for example, Baader Herschel Prism or Baader Astro Solar Safety Film). Using without the appropriate safe solar filters can cause permanent damage to the these filters and eyesight.
Moon Filter 
