A pack of M8 x 1.25 pitch x 12mm Hex self-locking flanged nuts for use with exhaust manifold studs. The slight oval shape these nuts provides anti-vibration properties and allows them to act as a self-locking nut, with it's full metal construction making it suitable for use on high temperature components. The flanged base allows for the pressure to be distributed over a greater contact area, with the copper flashing providing an anti-seize coating which helps to eliminate seizure on the manifold studs.