Bondage mitten
From wipipedia.org

A bondag emitten is a in effect a leather bag attached to a wrist cuff, the bag encloses the hand and makes manipulation of objects (such as undoing straps) virtually impossibe. The are two basic designs of bondage mittens; one with a loose fitting bag (often with D-rings attached to the end), and one with a much closer fitting bag which holds the hand clenched in a fist. The latter type is often used in animal play where sub is made to walk around on all fours.