Fitting Instructions1) Cut door aperture to the appropriate dimensions - 2) Separate the two letterplate halves and place the exterior gasket over metal fixing posts - 3) Take the half that contains brushes and insert into the aperture from the inside of the door - 4) Take the exterior half (with gasket) and slide into the letterplate tube from the outside of the door - 5) Before fixing. Take time to ensure the letterplate fully covers the aperture on both sides and that the exterior gasket does not protrude - 6) Use either the 2 short OR 2 long bolts (depending on your door thickness) and screw into centre hole at either end of the letterplate, ensuring that you DO NOT TO OVER TIGHTEN fixings -.