The two levels of PEP buddy (Level 1 and Level 2) have different levels of airflow resistance and hence create different levels of back pressures. You may find that a certain Level works better for you. Most people with COPD find it easy to start with a Level 1 device and then either progress to Level 2 or keep using Level 1. People who are new at practicing mindful breathing will find Level 1 device easier to use. But for those who already practice mindful breathing, Level 2 device may be better.