Dal libro "Signs of Honour", sezione Germania Hessen-Kassel (autore noto):
Order of the Iron Helmet
It was instituted by the Elector William I of Hesse on March 18th 1814 as a counterpart to the Prussian Order of Iron Cross. It was conferred on members of the armed forces of Hesse (both natives and foreigners) who attained distinction during the Napoleonic campaigns for acts of exceptional courage in battle. It was only conferred between 1814 and 1816 and came in three classes (although the Grand Cross and the first class were never awarded).
Badge: a cross patteé with lengthened arms in iron with silver margins affixed to the centre of which is a medieval suit of armour in iron, with a shield bearing the initials ‘WK’ (William Elector). On the lower arm of the cross is the foundation date ‘1814’. Some versions of this badge have a cross with trilobate arm ends.
Ribbon: red with a white band down both sides.

informazioni vengono comunque fornite anche nel sito segnalato:
http://gen.declercq.free.fr/phaleristiq ... CASSEL.htm