New GD402G units come measuring gas density as the default setting. This video shows you how to set the unit up for hydrogen purity measurement. Also, this video shows you how to change units for pressure, temperature and density. Alarm setting instructions are also contained in this video. While we strive to provide the safest and most accurate information possible, we are not responsible for any loss or damages resulting from attempting to replicate the acts conducted in this video. Furthermore, we shall not be held liable for use or misuse of information contained in this video.