The locking method utilize the elasticity of steel itself; it is compelled to lock with axical locking. This product is designed for bad work surroundings and easy let-off nut. Its ability of locking is 3 times as stronger as traditional locking; this is its advantage. The locking method is radical three points, the thickness is much thinner than other products. It is suitable, especially when there is the restriction of space of screw thickness and you can't find any other substitutes.