A seat belt system for a vehicle may include a tongue configured to slidably engage a seat belt; a retractor coupled to a portion of the vehicle, the retractor configured to receive the seat belt; and a height adjuster. The height adjuster may include a guide webbing configured to be secured to a portion of the vehicle; a frame supporting a locking mechanism; and a supporting surface to support the seat belt as the seat belt changes direction. The position of the frame relative to the guide webbing is adjustable. The locking mechanism is configured to lock the frame in a position relative to the guide webbing by clamping the guide webbing without input from the user and stays in position during a crash.