An electromagnetic switch is described as including a starter relay, in particular, for an electrical starter motor for controlling a starter pinion when starting an internal combustion engine, having a housing, an armature electromagnetically controllable therein, for controlling a control lever, and having a flexible protective cap which seals a transition from the housing to the armature, the protective cap being developed to be pot-shaped and having a pot floor and a pot opening, the pot floor having a circular opening having a thickened ring for the form-locking connection to the armature, and the pot opening being developed reinforced at its circumferential edge for the form-locking connection to the housing, the pot floor having a setpoint bending region, as seen in cross section. In order to create a small installation space, the protective cap has an arrangement or structure, on its inner wall, for connecting to the housing, which are able to be connected to the housing in a form-locking manner.