Head crusher
An instrument known since the Middle Ages, it enjoy the favor of many people in many parts of the world even nowadays. The chin of victim was placed above the bottom bar, and the uppercap lowered by the turning of screws. The teeth and then the jawbones broke till the cracking of the skull bone. Modern versions are filled with soft materials which leave no trace on the flesh of the victim, who however is ready to collaborate with questioners after a few turning of the screws.