An external cushioning system for a helmet includes an outer shell disposed outwardly of an outer surface of a helmet; an absorptive layer between the outer shell and the outer surface of a helmet; and an attachment mechanism to couple the external cushioning system to the helmet. The identified type of movement is compared with types of movement already stored in the control unit. The first wall defines a cavity recessed from an interior face thereof and in communication with the central slot in a transverse direction. The method can then extract from received video data frames the display order number, andor the number of reference frames and temporal level parameters, and detect that one or more frames or packets are missing. In another exemplary embodiment, the Token may be used to update the case file based on user input on the Token. The exhaust purification apparatus carries out a regeneration process of the filter based on the information stored in the storage device when the time for regeneration of the filter has been reached.