lobster pot

As pikemen were required to engage the enemy closely, they frequently wore steel helmets and a cuirass that is both armored breast and back plates. The helmets, or pots or lobster pots, were slightly angular round helmet[s] with […]

... should have been tucked behind his driver's license—and Larry saw the photograph—Marie and Sean in the kitchen wearing lobster pots for helmets and wielding frying pans for rapiers—but his driver's license appeared to be missing.