SVBONY SV139 Neutral Density(ND) filter is suitable for 1.25-inch eyepieces. The filter can reduce the overall brightness of the moon's surface. so you can see more details and surface features of moon with your telescope. There are several different strengths. The 1.25'' Neutral Density Moon filter reduces glare, so you can see more lunar details and surface features with your telescope. The metal filter cell threads directly into the 1.25'' barrel of your telescope eyepiece. These filters result in perfectly neutral color will not alter the natural color of the moon. ND0.6 transmits 25% of the incoming light ND0.9 transmits 12.5% of the incoming light ND1.2 transmits 6.25% of the incoming light ND3 transmits only 0.1% of the incoming light Four different sizes for you to choose from. Different sizes suitable for different moon phases: ND0.6 filter is suitable for waxing crescent moon ND0.9 filter is suitable for first quarter moon and last quarter moon ND0.9 filter is suitable for Waning gibbous moon and waxing gibbous moon ND3.0 filter is suitable for full moon observation Specifications Model W9108A W9108B W9108C W9108D Size ND0.6 ND0.9 ND01.2 ND3 Type Neutral Density Filter Material Aluminum Frame, Metal Thread and Optical Glass Barrel diameter 1.25'' 1.25'' 1.25'' 1.25'' Optical density value 0.6 0.9 1.2 3.0 Transmission 25% 12.5% 6.25% 0.1% Thread Standard M28.5*0.6 Standard M28.5*0.6 Standard M28.5*0.6 Standard M28.5*0.6 Suitable moon phase Waxing crescent moon first quarter moon last quarter moon Waning gibbous moon Waxing gibbous moon Full moon
