Neewer 1.25 inch Neutral Density 13 Percent Transmission Telescope Eyepiece Moon Filter(Black) The 1.25 inch 13 percent Transmission Moon Filter reduces glare so you can see more lunar detail and surface features with your telescope. Metal filter cell threads directly into the 1.25 inch barrel of your telescope eyepiece. Especially useful for large aperture telescopes through which the light of the Moon can be extremely overwhelming. Telescope eyepiece filter transmits only 13 percent of the incoming light, boosting contrast and ability to discern detail on the Moon. Perfectly neutral color will not alter the natural color of the Moon.