Abstract: Described herein is a pet restraining device, for use in vehicles, the comprises a shackle and a strap having two closable hooks or the like. Preferably, the length of the strap is adjustable. The shackle comprises a central loop and two overlapping end loops, all of which define substantially one plane. This invention is used by attaching the shackle to the seat belt of an automobile. The shackle is designed so that it can be easily attached to a fastened seat belt or to a seat belt that is an integral, closed loop. One end of the strap is hooked to the shackle, and the other end of the strap is hooked to a collar or harness on the pet. Although the preferred embodiment comprises a combination of a strap and a shackle to be used as a pet restraining device, the shackle element can be used in a variety of applications.