Here it is which I am led to believe is a Postwar German Fire service helmet but I stand to be corrected. Dimensionally it is about the same as the WW2 military service helmet but it does feel fractionally lighter and so perhaps is made from a thinner steel? The ventilation holes differ to the WW2 military version but are similar to the Luftschulz. The rim is about the same as the WW2 military version and it does not have the ribbed band. The Luftschulz helmet appears to have a wider rim.