1,Purpose: steel structure fastening, etc 2,Quality ... 15481, ISO 15482, ISO 15483,Modified Truss Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO ... 15480, ISO 15481, ISO 15482, ISO 15483,Countersunk Head Self drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO ... Head Self Drilling and Tapping Roofing Screws;DIN7504K,SAE J78,ISO 15480, ISO 15481, ISO 15482, ISO 15483,Concrete Screw ...