Spencer, through its cultural technique, has been able to identify two kinds of cervical immobilization -YES Immobilization & Silent Immobilization. In YES Immobilization it allows the patient to reply "Yes" when they are asked by the operator if all is well. Silent Immobilization does not comply with the YES technology and so the patients have to respond by moving their head because it is impossible for them to speak. This movement could be damaging and cause further serious injury. The possibility of an error is eliminated by placing a double valve collar around the patient's neck and helps in the correct extension of the cervical column. The collars are available in thermo-pressed, biocompatible, closed-cell polyethylene which guarantees excellent efficient.