Anti-draught ventilators can be installed in new and existing walls
To fit into an existing build: stitch drill and remove brickwork to one brick wide x either one or two brick high, and fit the sloping away from the inner wall
Large flanges around the external cowl and internal grille allow for minor irregularities to be covered easily and also adequate fixing
An external cowl will push onto sleeve and can be silicone sealed to face or screw fixed
