Roofing Bolts with Square Nuts - Zinc M8 x 40 Manufactured with a large flat head, which distributes the load across the fixing to increase the clamping effectiveness. Making it ideal for clamping thin sheet metal, plastic and wood. Thread Type Metric Recess Type Cross Finish Zinc Head Ø (mm) 19 Nut Size (mm) M8 MOQ Increment 1 Material Carbon Steel Corrosion Rating (1-5) 1 - Clean, dry & low humidity environments Head Type Dome MOQ 1 Thread L (mm) 40 Included Items M8 Square Nuts Thread Ø (mm) M8 Point Type B Point Substrates Hardwood, Softwood, Plastic, Steel, Thin Sheet Metal Nut Socket Size (mm) 13 Nut Type Square Thread Coverage Fully Threaded