The instrument consists of two forks set against each other that penetrated the flesh under the chin in one end and the upper chest in the other. As usual, this instrument didn't harm any vital points; thus avoiding death and prolonging pain.
The victim's hands were tied behind his back to prevent any chance of escape. The Heretics Fork made speech and neck movement almost impossible and was used after a confession to avoid hearing the victim any further. As can be seen in the picture, a small collar supported the fork forcing the victim to hold his head erect.
Sometimes the victim was incarcerated and subject to this instrument as well. This instrument often harmed the neck of the victim, as well as potentially spreading an infection or disease.