***** **********Best Quality Guranteed. ***** 1.25 inch moon filter reduce the amount of light entering the eyepiece and increase the eyepiece contrast*****The moon filter reduces the glare; allowing transmission of only 13 percent of the reflected ligh; which means you can see the surface more clearly and study the Moon in greater comfort*****Allow for maximum contrast of lunar detail enhances the contrast of the moon and planets in photographic images*****Neutral colored optical glass does not change the moon's natural color*****Have a standard 1.25 inch filter thread (M 28.5 x 0.6 )