A seat belt height adjuster is used to adjust the shoulder height of the seat belt. One end of the slider is biased by the bent spring so that a portion of the slider is spaced from the rail and to position locking protrusions on the slider body into at least one opening in the rail to lock the height adjuster at the desired height position. To adjust the location of the slider along the rail, a pushing force on the one end of the slider compresses the spring and removes the locking protrusions from the rail opening thereby allowing sliding of the slider along the rail. The slider pivots about its other end which is engaging the rail. Upon the release of the pushing force, the spring expands and biases the locking protrusion into a rail opening. The spring may be a simple V or U-shaped, leaf spring and the slider may be a single, integral piece of metal.
The seat belt height adjuster can be easily fitted to any car with access to the rear seat (i.e hatchback and estate cars), and can be used on the back seat or the front passenger seat. Once installed, it is unobtrusive and can stay in place permanently.