Product Name : Hex Flange Nut;Fastener Type : Hex Serrated Flange Nut;Thread Diameter : M8/ 0.31 inchThread Pitch : 1.25mm;Flange diameter (d1): 18 mm / 0.7 inches; Width of an area (e): 14 mm / 0.55 inchesflat width dimension (s): 13mm / 0.51 inch; Nut height (m): 8mm / 0.31 inchMaterial : 304 Stainless Steel;Color : Silver ToneFeatures:A flange nut is a nut that has a wide flange at one end that acts as an integrated, non-spinning washer.This serves to distribute the pressure of the nut over the part being secured, reducing the chance of damage to the part and making it less likely to loosen as a result of an uneven fastening surface.The flange may be serrated to provide a locking action.The serrations are angled such that they keep the nut from rotating in the direction that would loosen the nut.Because of the serrations they cannot be used with a washer or on surfaces that cannot be scratched.The serrations help in avoiding vibration of nut and increase the holding power of nut.Package : 20 x Hex Flange NutOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.