Hex washer head self drill with EPDM rubber metal beaked washer for metal roofing and siding ��The hex washer head self drill come with a drill point (TEK) for attaching metal roofing and siding panels to metal stud framing. * These screws come in #8, 10, 12 and 14 diameters and come as long as 6" long. ��They are��normally��fully threaded minus the drill point. ��Drill points come in TEK #2, 3, and 4-5. * TEK self drills are based on the thickness��of the metal you are��penetrating, the typical 25 to 16 gauge will use a TEK 3 and 14 gauge and below will require TEK 4-5. * The EPDM (Ethylene Propylene Diene Monomer) rubber which has a wide range of application. ��This is the best rubber for metal building and siding applications to stop water from entering the building with long life spans. * The fasteners and metal backed washer is made from 410 stainless steel.