Fitting Instructions1) Cut door aperture 285mm X 50mm2) 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. Enhance your door's functionality with this internal draught excluder letterbox. Featuring integrated brushes to block draughts and an internal water seal to prevent leaks, it ensures your home stays comfortable and dry. The anti-snap flap opens a full 180 degrees, allowing easy access and reducing the risk of damage. With an adjustable sleeve, this letterbox fits doors 40mm to 80mm thick, making it suitable for most uPVC, composite, and timber doors. The 12-inch length ensures a perfect fit for your needs. CHECK SIZE & FIT BEFORE PURCHASE – Letterboxes come in 10" or 12" sizes and suit different door depths. This model is 12" (30.6cm) and fits doors 40–80mm thick only. Some doors may also have slimline letterboxes, which are longer and narrower. Please measure your current letterbox and door depth carefully to ensure compatibility. ANTI-SNAP FLAP – The flap opens a full 180 degree for easy access and to prevent it from snapping off when opened too far. ADJUSTABLE SLEEVE – The telescopic design means the letter box can be adjusted to fit doors between 40mm to 80mm in thickness. Our letter box will fit most uPVC, Composite & Timber doors. DIMENSIONS – The letter box overall size is 306mm x 70mm and the internal dimension of the sleeve is 254mm x 37mm. The distance between the screw hole centres is 280mm. Suitable for apertures between 285mm x 50mm up to 295m x 60mm. INTERNAL DRAUGHT EXCLUDER – The integrated brushes help prevent draughts. Plus, an internal water seal prevents water leaks as it stops water getting into the door or panel. EASY TO INSTALL – Please read product description below for a simple guide on how to install the letterbox., Manufacturer: Keypak