Excel & Plus: Lowest point possible with 1” minimum space for airflow throughout the humidor. Ultra: Lid mount or upright, allow for 1” minimum space for air to flow.Magna: Base should be as low as possible with vent flaps/fan facing the back or side of the humidor to promote airflow up, allow a minimum of 1” spacing in several shelves for air to flow. Place the remote inside the humidor approximately 9”-12” above the base for best regulation of Humidity.