iron expand screw M8 Length: 48mm, outer diameter: 12.7mm, Thread: M8 Weight: 18.9g Finish: zinc plated iron expand screw M8length: 48mm; outer diameter: 12.7mm, inner screw thread: M8Weight: 18.9gFinish: zinc platedMaterial: carbon steelUsage:to fix an air condition, water heater, oil obsorption; balcony window, etc(to punch a hole of 8mm in size first)