A Passover humidifier is used in conjunction with an nPAP machine to produce cool moisture, which flows from the nPAP, through a chamber filled with cool water, and to the mask. The purpose of a Passover humidifier is to keep the patient’s nasal passage from becoming dry and sore. A Passover humidifier is not plugged in to an electrical outlet and does not have a heater plate.
See: https://www.cpap.com/productSearch.php? ... humidifier