Height adjuster for an automobile seatbelt

The adjuster (2) has a guide rail (1) fastened to a vehicle side, and a carriage (23) that is relocatably held along the guide rail. The guide rail includes rest windows spaced apart in a longitudinal direction (12) and hook-like retaining units (13), which are formed out of a material, where the hook-like retaining units are inserted into respective slots. Components of the hook-like retaining units are engaged underneath areas of a vehicle structure or a vehicle sheet metal in a target assembly position.