Refillable cartridge to seal in the Agave vapor infusion for added moisture and superior condition and shine. *Use only the Agave Vapor Infusion. PLEASE NOTE: There are TWO versions of the Refillable cartridge, the NEW version and the ORIGINAL version. When ordering please verify you have selected the correct item: NEW: the cartridge is located closer to the bottom of the iron, the cartridge has thumb grip ridges at the top of the cartridge, clear backing ORIGINAL: the cartridge is located in the middle of the iron, the cartridge itself has the thumb grip ridges in the middle of the cartridge, black backing.