These nickel-finished darby-style cuffs are made of high quality brass. The appeal of darby-style restraints is that they are historical representations of old style handcuffs. While they can't be used by a modern police force, their look and design still make them a functional item for bondage use. They feature multiple locking positions and include two keys. The inside perimeter is 7.5" adjustable to 8.25". They weigh 18oz.