1. Rotate the filter housing to adjust the light transmission from 1 to 40 percent 2. Reduces the brightness of the Moon or planets for a clear field of view 3. Provides better control of image brightness than standard fixed transmission telescope filters 4. Material: optical glass lens + aluminum frame 5. Diameter: 1.25 inch 6. Net weight: about 13g 7. Glass material thickness: about 2.4mm
