Used for stitching two metal roofing sheets together without the need to pre-drill a hole (Max. 1.6mm). Self-drilling point and tapered shank, with a washered hexagon head. Exterior plating gives a reliable and durable corrosion resistant coating which resists 500 hours salt-spray" Thread Dia. mm: 6.3 Length mm: 22 Head Type: Hex Fixed Washer Dia. mm: 12.00 Point Type: Self-Drilling No.2 Reduced Socket Size mm: 8 Finish: Exterior (Silver Organic) Material: Case & Core Hardened Carbon Steel Effective Thread Length mm: 9 Max Drilling Thickness mm: 1.6Size 6.3 x 22 - 100 pcs Timco Metal Stitching Screws - Sheet to Sheet Hex EPDM Washer Self-Drilling in Silver