These hold ones wrists and ankles in line with each other. Much like the Fetters Rigid Handcuffs + Leg Irons Combination except that the Leg Irons are larger in diameter, 4", intended to fit over boots. Smaller legged individuals could probably shake the Leg Irons off, IF they could remove the boots with their wrists in the cuffs. One cannot move at all while wearing these not to mention the pain in the back, over time. Obviously intended as a torturous as well as restraining device. They have a single "standard" allen wrench bolt lock.