The 54.6 cm (21.5 inch) [477 x 268 mm] is the screen size of a specific device that our website sells a range of screen protectors for. This size is important to know when selecting the appropriate screen protector for your device, as it ensures a perfect fit and maximum protection. Our website offers a variety of screen protectors for this size, including tempered glass, anti-glare, and privacy options, all designed to keep your device's screen safe from scratches, cracks, and other damage.