Maybe it's not the product but I expected them to fit standard screw head sizes. They don't. A half inch fits a 5/16 inch stud, which is an odd size for most jigs. I wish he had made 7/16" slots for 1/4" screws and 9/16" slots for 3/8" screws. Otherwise they are of good quality as you would expect, they will work quite well for a long time.