Hex head self-drilling screws, for joining roofing sheets to light section steel (Max. 5.0mm) without the need to pre-drill a hole. Hardened carbon steel drill tip fused on to an A2-304 Austenitic Stainless Steel body" Thread Dia. mm: 5.5 Length mm: 100 Head Type: Hex Fixed Washer Dia. mm: 11.00 Point Type: Self-Drilling No.3 Socket Size mm: 8 Material: Bi-Metal/A2-304 Stainless Steel/Carbon Steel Effective Thread Length mm: 87 Max Drilling Thickness mm: 5.0Size 5.5 x 100 - 100 pcs Timco Metal Light Section Screws - Hex - Self-DrillingBi-MetalExterior in Silver