The 9 cm (3.6 inch) [54.3 x 72 mm] measurement is a reference to the size of the screen protector that is compatible with a specific device. Our website sells a range of screen protectors that are designed to fit different devices, and this measurement helps customers identify the correct size for their device. By providing accurate measurements, we ensure that our customers can find the right screen protector to protect their device's screen from scratches, cracks, and other damage.