The Block Shaft® Classic anti-theft device consists of an auxiliary mechanical device of high safety and resistance, capable of preventing the directionality of the vehicle. It is basically a locking device that is implanted on the steering transmission system, without making any structural and / or functional changes to the construction characteristics of the vehicle. In particular, the device consists of a quill welded on the stator part of the column and a padlock that slides inside until it engages in a slot obtained on a bush integral with the shaft of the same column. The device is activated through a safety lock certified according to the UNI N1303 European standard called Netoma®. The alarm is inserted with straight wheels; from this memento onwards the activation is completed and the key can be withdrawn.