One type of shackle, called an "Oregon Boot" or "Gardner Shackle", was patented by Oregon State Penitentiary Warden J.C. Gardner in 1866. The shackle consisted of an iron band of varying weights that was locked around one of prisoners ankles that was supported by braces which went down and under the prisoners foot. The shackle's weight hobbled the prisoner's movements to prevent escape, and long-term use would cause severe injury to the wearer. Use of this type of shackle was ended by the mid-20th century.