The Boundless CF mouthpiece assembly is a replacement device that is also compatible with Boundless CFX vaporizers. The mouthpiece comes ready to use with the seal, cooling unit, stainless screen and the O-ring. This is an original factory replacement so you can be assured of a perfect fit for your vaping device. You don’t need any modifications when you buy the Boundless mouthpiece assembly set. It's recommended to replace the mouthpiece to ensure that the vaping experience is not diluted by the stale taste or the airflow is restricted due to the filters and mouthpiece.