Either 1 of them is free of defect or 2 of them are free of defect or 3 of them are free of defect or 4 of them are free of defect or 5 of them are free of defect or 6 of them are free of defect or 7 of them are free of defect or 8 of them are free of defect or 9 of them are free of defect or 10 of them are free of defect or 11 of them are free of defect or all 12 of them are free of defect. Or-- Not all of them are defective. Edwin