The RW Simon Vent-A-Matic circular window vent is a non-electric window ventilator designed for kitchens, bathrooms, and bedrooms with an average room size of 9000mm2. The RW Simon Vent-A-Matic Model 106 is sized to fit holes measuring 162mm (6.5 inch). The vent is equipped with a diffusing rotor to prevent draughts and improve fresh air distribution, helping to prevent condensation in most sized rooms. The rotor is designed to operate on its own inertia even when air pressure is equalised. This controllable ventilator provides the ideal solution to control condensation in most rooms. Each model is equipped with a diffusing rotor which helps to prevent severe draughts and improve fresh air distribution within the room. The rotor continues to operate under its own inertia, even when air pressure on each side has been equalised. Simon Vent-A-Matic single glazing ventilators are designed for single glazed windows.