The specialty of the M2 is the back, which is perfect, and its arc surface full of tension. When you hold the M2, the radian of the back fits closely to your palms. We use stainless steel, because of its smooth and cooling sensation and the good feeling for grip that it provides. In order to seek the complete body, we design the whole surface through the top and bottom of the curve extension to the front side of the phone, which makes it simple and clear. We gave up digging holes in the glass out of the sounds, and set the speaker in the edges of the top and bottom glass. The voice will be released without reservation through dense and orderly holes.