DESIGN: The Acme Turbine Vent is a turbine vent designed to move warm, humid air which can create moisture damage on top of a commercial roof. It is powered by the wind and requires no electricity to operate! COMMERCIAL GRADE MATERIAL: The Acme Turbine Vent is available in either durable PVC or 60-mil TPO construction DIMENSIONS: The vent measures 18” H with a 12” top diameter and a 14” bottom diameter You know that a properly ventilated roof is key to its performance and lifespan. Wrong or improper ventilation can cause condensation and moisture build up that can cause the system to prematurely fail. The Acme 12″ Turbine Vent is available in either 60-mil TPO or PVC. It measures 18″ in height. The top diameter is 12″ and the bottom diameter is 14″. The Acme 12″ Turbine Vent comes with a metal flange 4″ in length and a 6″ membrane flange.