The 54.9 cm (21.6 inch) [464 x 290 mm] is the screen size of a specific device that our website sells a range of screen protectors for. This measurement is important for customers to know as it ensures that they purchase the correct size screen protector for their device. By providing this information on our website, customers can easily find the right screen protector that will fit their device perfectly and provide optimal protection against scratches, cracks, and other types of damage.