This adjustable mushroom vent can be fitted to most steel or glassfibre roofs and ensures adequate,
adjustable ventilation. This vent is designed for a roof 25-25mm thick. If your roof is thinner, parts of the vent can be shortened. Aperture needs to be 130mm External diameter is 190mm To allow the vent to close and open a small circlip has to be removed from the centre, by first removing the three screws holding the dome in place