Just outside Stuttgart in the city of Esslingen (on the Neckar River) was once located the metal fabrication firm of Quist which manufactured steel helmets during World War II.  So successful was the firm that it was also contracted to manufacture "M1940 style" helmets for the postwar West German government.  These helmets were intended for use by border guard police serving in the protected zones between East and West Germany.  Quist made helmets were marked with a very pronounced "Q" on the inside left rim.  Next to the "Q" mark was placed a two digit numeric stamp denoting the actual shell size of the helmet in centimeters.  While early production helmets had their markings on the left inside rim, sometime after 1943 the firm moved the shell markings to the rear of the helmet.  Helmets made by Quist were noted for their thick metal and well shaped proportions generally showing high craftsmanship.  The firm produced all three types of steel helmet including the M1935, M1940, and M1942.  Quist made helmets were supplied to the German Army (Heer), Air Force (Luftwaffe), Navy (Kriegsmarine) and Field Combat Police (Feldpolizei).  The Armed-SS (Waffen-SS) also requisitioned a large number of helmets from this firm including the M1940 double decal SS helmet.