This telescopic underfloor ventilator is to be used with Timloc’s Airbrick. It is placed beneath suspended ground floors to create a form of ventilation. This ventilator is vertically adjustable and so is suitable for use with brick courses between 225mm and 375mm (3 to 5 brick courses). Its minimum cavity width is 50mm. The specially designed front grille is used to prevent vermin from entering your roof space and drastically reduces the amount of rain blown in by strong winds. They are created by injecting polypropylene (PP) that has been treated through UV stabilisation, into a mould. Features & Benefits Adjustable to 3 – 5 brick courses Sturdy and tough Completely resistant to deterioration and decay Manufactured to BS EN ISO 9001 and BS EN ISO 14001 standards Product Specification Area Per Vent: 6000mm² Colour: Black Pack Size: 20 Size: Standard - 220mm x 225mm Extended - 220mm x 375mm