MYLAR® OL3 is a biaxially oriented polyester film with a thick amorphous polyester heat seal layer designed specifically for giving leak proof/peelable seals to ridged APET coated card trays and smooth walled aluminum foil trays.  

MYLAR® is a registered trademark of DuPont Teijin Films for its polyester film.  Only DuPont Teijin Films make MYLAR®