Adjustable ventilator to provide ventilation beneath suspended ground floors between 5-7 brick courses. With incorporated grille to prevent vermin entry.The vertical height of the ventilator unit adjusts to suit between 5 and 7 brick courses (375mm-525mm) with a minimum cavity width of 50mm.We have an extensive range of easy-to-fit horizontal and vertical extension accessories, that do not restrict airflow, to adapt the unit for various applications.