Active Ventilation Products offers the Aura Ventilator.

Active Ventilation Products, Newburgh, N.Y., offers the Aura Ventilator. It exhausts like a turbine, with no moving parts. It is non-electric, made from heavy-gauge aluminum and is maintenance-free. The ventilator ranges in diameter openings from 4 to 48 inches. Accessories such as skylights installed onto the lid, collars to increases stack heights, electric fans and automatic or manual dampers are available.