Lee Marvin died shortly before filming began, so his character was written out of the film.
Maj. Wright:
They might come in handy on the next mission.
A US WWII M1 steel helmet consists of two major parts, the outer steel shell which affords some ballistic and fragmentation protection together with the inner lightweight (non-steel) helmet liner. Telly Savalas wears the helmet liner without the steel shell - that would never occur in combat. It is a common Hollywood war movie cheat to reduce fatigue and strain on the actor's head and necks.
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