In 1940, standard practice in the German Police was to grant equivalent SS rank to all police generals. Police generals who were members of the SS were referred to simultaneously by both rank titles - for instance, a Generalleutnant in the Police who was also an SS member would be referred to as SS Gruppenführer und Generalleutnant der Polizei. In 1942, SS membership became mandatory for police generals, with SS collar insignia (overlaid on police green backing) worn by all police officers ranked Generalmajor and above.