UHC filters are designed to increase the image contrast of your subject Substrate: Precision polished substrate, good parallelism, precise 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<br><br>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 observation. Colour:As Shown Material:Glass<br><br>Package Contents: 1x Light pollution suppression filter<br><br>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.