EN 443:2008 differentiates between "Type A" and "Type B" helmets. The HEROS-smart is a "Type A" helmet. The HEROS-xtreme is a "Type B" helmet:

• The "Type A" helmet has a half or three-quarter shell. This means that it does not cover the entire head, but ends at ear level. Please see the the helmet photo of the yellow HEROS-smart on the right.
  
  
• Conversely, the “Type B” helmet is of full shell design, with a shell that extends to the chin and thus covers the whole head of the wearer; as shown by the luminous HEROS-xtreme helmet on the right.
  
  

The differences between the Rosenbauer helmets HEROS-xtreme and HEROS-smart are
shown in the table below: