sentences:  [Notes 4]
  
  The BK Stacker sandwiches are a discontinued family of hamburgers featuring the same toppings that targets the late-teen–to–young-adult and male-oriented demographic groups.It is a cheeseburger consisting of anywhere from one to four grilled beef patties, American cheese, bacon and Stacker sauce served on a sesame seed bun.The BK Stacker was first introduced in the summer of 2006.