The Coolus Mannheim helmet was a cavalry helmet during the Roman era. The original artifact of the Coolus helmet was found in the river Marne of Coolus and this is from where it got its name. It is also known as the Coolus Mannheim (Type A) by Schaff. The helmet is shaped like a hat with slight neck protection. The rim of the helmet is folded on the inside to prevent any roughness. A single belt-to-buckle attachment was given to the helmet to keep it firm on the head of the cavalrymen.