Features:  Owing to the high hardness, sturdy texture and durable property, this self drilling expansion screws set can be used as practical tool for fixing on the drywall, slate, wallboard and plasterboard.  Due to the excellent design of this self drilling expansion screws set such as easy operation, expansion function, sharp head and special serrated design on both sides, it can give you a great convenience in attaching and removing screw on the wall without leaving a conspicuous hole. Its convenient property also appears on no hole or drilling required during assembly process.  Made of high quality metal, it is sturdy and wear-resistant.  There are two styles of different sizes to be chosen. .