What is a Sems screw? Well, it isn't what type of screw it is it has more to do with what the screw has with it. Rather than purchasing screws, then washers and assemble them yourself, they are manufactured automatically with some type of washer to the head. There are standard type wahsers with locking external tooth and internal tooth listed here. Other types are available as well sof you need help locating your specific need, contact the sales team at CFI
we are here to help.