Hex head self-drilling screws, for joining roofing sheets to light section steel (Max. 4.5mm) without the need to pre-drill a hole. Fire Classification: A1" Thread Dia. mm: 4.8 Length mm: 13 Head Type: Hex Fixed Washer Dia. mm: 10.00 Point Type: Self-Drilling Socket Size mm: 8 Finish: Zinc Material: Case & Core Hardened Carbon Steel Effective Thread Length mm: 4 Max Drilling Thickness mm: 4.0Size 10 x 1/2 - 1000 Pieces Timco Metal Construction Light Section Screws - Hex - Self-Drilling - Zinc in Silver