A method for treating hair which comprises:. The at least one retention element extends across the entire length of the sleeve and has a head having a connecting neck in its cross-section. The server retrieves an emergency institution with reference to the position information and relays the emergency call to the retrieved emergency institution. While the downward force is released, the gas releasable valve is automatically switched for allowing gas transported to the gas emitting nozzles to produce the visible flame. In addition, the system saves the embedded metadata and the additional metadata on the storage medium in a searchable format. In some embodiments, the relationship between a cartridge of the module and its corresponding head prevents fluid from entering between the cartridge and an external shell of the module.