Cowled Ventilation Grille with Back Draught Shutter. Suitable for use with 100mm / 4 Inch diameter ducting. Features concealed fixing points. Fixing screws and rawlplugs are not included. Dimensions: 155mm tall x 155mm wide x 70mm projection. 99mm diameter spigot extends for 20mm. Fixing points are 107mm horizontally / vertically.