Head and bell type internal locking system consists of two rings piano constructed that are activated when placed in the tip of the head, preventing the return thereof.
It has an external protection that gives greater security to the main rotor, easy application mechanism, it must have a crank that rotates clockwise, which must be broken after its application.
For application in difficult places, the seal body has a pellet type system that secures the cable to be activated, unable to return to give more anchor.