Vent-Axia T Series Traditional 12″ Roof Fan is suitable for installation in horizontal, angled (max pitch 30deg) and vertical glass and for fixing plates in roofs. For vertical windows or walls in exposed areas and single or double glazing including most types of glass up to 32mm thick. Greater thicknesses can be accommodated using extended fixing rod sets. All four sizes of Vent-Axia roof plate assemblies can be fitted easily into flat roofs.