As we insulate houses and buildings with cavity walls, double glass, stone- and glass wool, one detail remains sadly ignored: the letterbox. A letterbox is an accepted heat leak and a source of waste. Unfairly. Start-up company Trim Trading took up this challenge and asked Promea to design an affordable letterbox with serious sealing and thermic insulation without any concession to ease of use. Behind the seamless brushed aluminium front, rubber seals and foam inlays are carefully integrated. Experts have confirmed the high claims of its physical characteristics. The fluorescent green torsion hinges on all four corners provide a subtle but unmistakable sustainable identity to the world´s first insulated letterbox!