Safely view the sun anytime and during all partial phases of an eclipse (viewer required for all phases of annular eclipse). Instructions for use. Inspect for damage before each use. Do not use with binoculars, telescopes,camaeras,or any other optical instruments. This device is not a toy. Children must be supervised .Use continuosly for up to 3 minutes, intermittently for several hours. Do not use after eye surgery or with diseased eyes. Optical density 5 .Safe for direct solar viewing. Thousand Oaks