These are Blu-Ray DVD divider cards! Our divider cards are professional heavy duty store grade divider cards. They are professional, heavy duty store grade divider cards - made out of 100% virgin high impact polystyrene (HIP). They are strong stuff - used by music stores all over the country! These cards are rectangles with rounded corners (it eliminates jabbing yourself on the sharp corners! ) Superior to the "tab" style dividers because those are more likely to snap off.