UHC filters are designed to increase the image contrast of your subject Substrate: Precision polished substrate, good parallelism, precise surface Simply mounts to the eyepiece and is housed in a rugged housing Double-sided fine polishing and polishing process ensures high parallelism coating Double-sided multi-layer coating, with a transparent film added on the back to reduce reflected light The High Contrast Filter (UHC filter) is the harmful light filter of choice, it is more perfect to significantly reduce light pollution and is suitable for urban and suburban observation. Colour:As Shown Material:Glass Package Contents: 1x Light pollution suppression filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.