how do i identfy this helment what do i look for it has been painted black on the out side but it is green inside no decals leather sweat band metric size these numbers stamped in the inside steel vdn564 and b7sorry cant post pics but it has no neck leather thanks for your help

It sounds like you have a model 1934 civic helmet, used for police & fire fighters. We would have to see photos in order to tell you any more.
Cheers,
Mike