Adjustment fitting for motor vehicle seats

The fitting has a coupling including a clamping body (28) that is moved along a trajectory. A cylindrical track (30) runs parallel to the trajectory and made of metal with a hardened surface layer (38). Another track forms a clamping contour, and is different from the trajectory. Hardness and depth of the surface layer of the former track are dimensioned such that the former track is softer than the latter rack. The coupling includes an inner ring (22) and an outer ring (24), where the inner ring and the outer ring are formed as the tracks, respectively.