Flange Nut is a nut that has a wide flange on one end and acts as an integrated non-rotational washer. This works to disperse the pressure of the nut over the fixed parts, reducing the possibility of the parts, and making it less loose as a result of uneven surface tightening. Flanges may be serrated to provide locking action. Seration is slanted to not rotate the nut in the direction that loosens the nut. Not for use on non-abrasive surfaces due to seration. Seration helps to avoid nut vibrations and increase nut retention. Specifications: Product Name: Hex Flange Nut Material: 304 Stainless Steel Main Color: Silver Tone Thread Size: M4(D) Height: 4mm Hex Width: 7mm Flange Diameter: 9.8mm Package Includes: 20pcs x Hex Flange Nuts