Also known as: サムカフ, 指錠
A smaller version of Cuffs used to shackle a person's thumbs. Commonly designed as a small, rigid metal device than can lock the wearer thumbs centimeters apart, but chain-linked, mini-Handcuffs version also exists. In Bdsm practice, it also commonly used to restrain someone's big toes (Toecuffs).