The 38.1 cm (15 inch) [331.6 x 186.6 mm] refers to the size of the screen that our website sells screen protectors for. This size is commonly found in laptops, notebooks, and some desktop monitors. By providing the exact dimensions, customers can ensure that they are purchasing the correct screen protector for their device. Our website offers a range of screen protectors that are specifically designed to fit this size, providing protection against scratches, smudges, and other types of damage.