Abstract: A device for introducing slack into and removing slack from a lap belt device while the device remains in its buckled configuration. The device has an inverted "T" configuration that includes a longitudinally extending first part that slidingly supports a shoulder harness and a transversely extending second part having return bends formed in its opposite ends that slidingly receives opposite ends of the shoulder harness to maintain the shoulder harness centered with respect to the first part. In a first embodiment, serrated teeth are formed in a lower end of the first part to grasp the harness and to prevent its sliding movement with respect to the first part of the device when the device is rotated from its unlocked position to its locked position. In a second embodiment, opposite ends of a rigid wire that is bent to form the device are transversely spaced apart from one another and perform the same harness-gripping function as the serrated teeth.