Abstract: An electromagnetic relay having a switching sensitivity alterable under the influence of an external magnetic field. The relay comprises a coil form made from an insulating material. A plurality of pole-shoes, also acting as relay contacts, are mounted in the coil form. A plurality of ferromagnetic inlays which exhibit magnetic lines of force are mounted in the coil form so that each one of the inlays is associated with a corresponding one of the pole-shoes. When the inlays are mounted, the magnetic lines of force exhibited by these inlays are not perpendicular to the corresponding pole-shoes. A magnetic insulating region is formed by the coil form for partially insulating the pole-shoes from the lines of magnetic force exhibited by the corresponding inlay. The relay contains a substantially flat ferromagnetic armature which is switched into one of two positions in response to an excitation coil which is sensitive to an electrical current.