1PREMIUM MATERIALS AND CRAFTSMANSHIP: This CPL filter is made of anodized aluminum frame, precisely ground and highly polished to ensure durability. 2ENHANCED CONTRAST: The use of two piece optical glass reduces the amount of light entering the eyepiece, thus increasing the contrast of the eyepiece. While viewing bright objects, such as the moon or certain planets, you can gradually darken the field of view to a level that simultaneously increases contrast, reduces glare, and increases the amount of viewable detail, depending on your needs. 3REDUCED GLARE: The polarizing filter reduces glare by allowing only 13% of reflected light to be transmitted, which means you can view the lunar surface more clearly and study the moon more comfortably. 4EASY TO USE: The polarizing filter has a standard M28.5x0.6 thread that is compatible with many telescopes. The 25inch polarizing filter is the universal lunar and planetary filter for starters. 5ROTATING ADJUSTMENT: By rotating the filter housing, light transmission can be gradually adjusted from 1% to 80%, providing fine control over image brightness and performance as needed.1 x Telescope Polarizing Filter1 x Storage Box