binifiMux 10Pcs M10 x 1.5mm Black Hex Nylon Insert Self Lock Nuts, m10,

Nylon lock nut is a round nut, and in its outer open four small slot, you can use the crescent wrench screw on the stud, the lock nut should be equipped with a shaft Washer, it can be used to make the small groove on the stud and its peripheral groove relative to the fixed, to prevent its loose.