Black polymer is the most common filtering material for observing sunspots and granulation, through telescopes and binoculars.;These sheets are a quality product of Thousand Oaks Optical, Arizona, a manufacturer of safe solar filters for over 30 years. Stronger than Mylar with the filtering properties protected within the substrate. Guaranteed five years.;Make a filter on your own for any telescope / binoculars / camera, and for a fraction of what factory made filters cost.;The sun will appear in a natural orange color when viewed through your telescope using this filter.;WARNING: ALWAYS MAKE SURE THE FILTER IS WELL ATTACHED TO THE TELESCOPE/BINOCULARS, USING STICKY TAPE, TO KEEP IT FROM FALLING WHILE OBSERVING!