Allied Autovent VentilatorAllied Autovent Ventilator Condition: Pre owned The AutoVent 4000 maintains the core features of the AutoVent 2000 and 3000. Pneumatic power and hard plastic case provide a sturdy, virtually unbreakable ventilator. It has the same controls for setting the clinical parameters of BPM, Tidal Volume and Inspiratory Time, but has newly added features which include an internal demand valve, anti breath stacking, adjustable maximum airway pressure from 20 80