Hex head self-drilling screws, for joining roofing sheets to light section steel (Max. 5.0mm) without the need to pre-drill a hole. Thread Dia. mm: 5.5 Length mm: 50 Head Type: Hex Fixed Washer Dia. mm: 11.00 Point Type: Self-Drilling No.3 Socket Size mm: 8 Finish: Zinc Material: Case & Core Hardened Carbon Steel Effective Thread Length mm: 35 Max Drilling Thickness mm: 5.0Size 5.5 x 50 - 100 Pieces Timco Self-Drilling Screws - Hex - For Light Section Steel - Zinc - with in Grey