I HAVE,THE PLASTIC LONG WIDE BOXES,THE RUBBERMAID,AS THE MAINE COONS,ARE TOO BIG,FOR THE REGULAR LITTER BOXES.AND YOU COULD TRY,A WIDE ,RUBBERMAID,THE LONG NARROW,ONES,THAT ARE LABELLED,UNDER THE BED STORAGE.GOOD LUCK,WITH LILY,LUNA,AND THE LITTER BOXES!