Features: 1. Multi layer anti reflection film 2. Non cement optical substrate coating 3. The electron beam gun evaporation technology using ion assisted deposition coating technology has durability, scratch resistance, and stability at CWL (center wavelength), which is not affected by temperature changes. 8. Prevent reflective laser engraving from fading 9. 90% transmittance of the main nebula emission lines (i.e. Ha 656nm, OIII 496nm&500nm, SII672nm, and H-beta 486nm). 10. 0.1% of out of band transmission, especially the main emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm, and 578nm). 11. Suitable for color CCD cameras and unmodified digital SLR cameras CLS with a wider passband than UHC is therefore more favored when observed under mild to moderate light pollution. 13. Light pollution filters will not eliminate the effects of light pollution or increase the brightness of objects. In many cases, they increase the contrast between the nebula and the night sky without brightening the nebula. 14. Warning: SVBONY's filters are not designed for sun observation. Do not use SVBONY filters to view the sun. If you do not follow the warning, you will become blind.