San Gimignano, Italy
All of them have common characteristics, in that they are covered with spikes on the back, on the arm-rests, on the seat, on the leg-rests, and on the foot-rests.
It's easy to comprehend the effect of the spikes piercing the victim's body made even more effective by a screw bar system to immobilize the victim and make the pins penetrate more deeply.
The bars, either made of iron or wood, fastened the victim around the waist, around the wrists, and around the chest or bust.
The seat was often made of iron that could be heated. These implements were used in Germany up until the 19th century, in Italy and in Spain up until the end of the 1700s, in France and in other central European countries, according to certain sources, up until the end of 1800.