SPECIFICATIONS - Head style 5/16” (8 mm) - Washer diameter standard 19 mm - Galvanised EPDM bond seal - Support thread - Thread for substructure wood - Drilling point 2 reduced Usage - For fastening wall sandwich panels in a vertical and horizontal arrangement - For fastening roof sandwich panels - For surface installation - For installation in board lock - For fastening sandwich panels to steel substrate Double thread screw manufactured by DD Fasteners are suitable for exterior roofing environment. Provide surface coating per customer request for surface corrosion protection. Different type of thread and point length available per customer environment requirement. From light work to heavy work, you could find solution by consulting Landwide sales team. And thread to point unique design provides quick and easy installation in the substrate without pre-drilling. Coating Mechanical Zinc, Zinc Plated Cr+6 , Zinc Plated Cr+3, Zinc Yellow Cr+3, Zinc Yellow Cr+6, Grey Phosphated, Black Phosphated, Ruspert 500HRS, Ruspert 1000HRS, Ruspert 1500HRS, Class 3, Class 4, Other Special Coating Website : Stay tuned Cheers Have a nice weekend