"The UAP Doormaster 12"" Polished Silver Letterplate is designed for secure, durable and smooth performance on uPVC, composite and wooden 40-80mm doors. With strong aluminium flaps, a telescopic adjustable sleeve and outward-facing draught-proof brushes, it provides long-lasting protection, improved insulation and reliable daily use. The patented anti-snap design, robust construction and simple self-aligning installation make it an ideal replacement letter box for any modern front door.Key Features• Quality Tested to BS EN 13724: Built to withstand over 100,000 opening/closing cycles for dependable performance.• Industry Standard Replacement: Trusted Doormaster design ensures smooth integration with a wide range of door styles.• 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."