1,Purpose: steel structure fastening, etc 2,Quality assurance preferential price 3,Prompt ... ,ISO 15480, ISO 15481, ISO 15482, ISO 15483,Hex Washer Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO 15480, ISO 15481 ... 15483,Nylon Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO 15480, ISO 15481, ISO 15482, ISO 15483,Concrete Screw;DIN7504K,SAE ...