Inline Slate Vent to enable ventilation directly into a roof space or connect to a ducted ventilation system. Uses: On roofs with Natural or Synthetic Slates, Enables ventilation directly into a roof space, Can also be connected to a ducted ventilation system inside the building. Features and Benefits:Suitable for roofs with a minimum pitch of 22.5°. Free ventilation area of 9,450mm2 Compatibility: Natural or Synthetic slates in sizes 600mm x 300mm or 500mm x 250mm from all major manufacturers.