The marking in red and the letter "S" indicates the zone where the groove (bearing ring) has hardened(s) (soft zone). For rings with a plugged bore, this zone coincides with the position of the plug.

The green marking on the gear wheel is the point of maximum runout of the pinion, to adjust lateral clearance.

Marks in black on the rings of certain bearings that have a narrow cross-section relative to their diameter. The position of these marks corresponds to the minimum ovality of the assembled bearing.