The 54.6 cm (21.5 inch) [477 x 268 mm] is the screen size of a specific device, and our website sells a range of screen protectors that are designed to fit this device perfectly. These screen protectors are made from high-quality materials that provide excellent protection against scratches, cracks, and other types of damage that can occur to the device's screen. By offering a range of screen protectors that are specifically designed for this device, our website ensures that customers can find the perfect screen protector to meet their needs and keep their device's screen looking like new for longer.