The 43.4 cm (17.1 Inch) [378 x 212.8 mm] is the screen size of a specific device for which our website sells a range of screen protectors. It is important to know the exact screen size of your device in order to select the correct screen protector that will fit perfectly and provide optimal protection. By providing this information on our website, customers can easily find the right screen protector for their device and ensure that their screen remains scratch-free and protected from damage.