Baader 1.25" two-part polarising filter

Baader Double Polarizing Filter

To screw into 1¼ or 2" eyepieces/threads. The two filters can be rotated against each other to always be able to achieve comfortable brightness level for moon observations, independent of moon phase. The Baader Double Polarizing Filter can also be used for solar observations in combination with an objective sun filter from Astro Solar Film.

The double polarizing filters in 1¼ or 2" can not be splitted 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 more 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 reflexions.