What is the difference between Resmai single-stage automatic ventilator, S9 two-stage automatic ventilator and single-stage automatic ventilator?

Household ventilator is not as expensive as possible, but suitable for you. If it is only snoring and sleep apnea syndrome, there is no problem with cardiopulmonary function, and a single-stage automatic ventilator can be used. If you are particularly obese and have an old heart, it is better to consider a two-stage ventilator, which is more comfortable.