"Complete your door with the UAP Doormaster 12"" Silver Draught Proof Letterbox, designed for smooth operation, secure performance and long lasting durability. Suitable for uPVC, composite and wooden doors 40 to 80mm thick, it features internal and external flaps that help reduce draughts, improve insulation and support easy everyday letter handling. The Doormaster design is built for long term reliability and tested to BS EN 13724 standards.• Distance Between Screw Holes: 272 mm• Letterplate Length: 300 mm• Letterplate Height: 74 mm• Letterplate Width: 40-80 mm• Cavity Hole Size: 257 mm × 42 mm."