5K DAC/AMP has four buttons, two left, two right.
We placed them in the upper corners, so it would be more comfortable to operate them.
We also placed a red LED in the left button, and a blue LED in the right.
You can quickly check which one is which, seeing the light.
Lastly, one button is flat, but the other one is not.
You can distinguish the difference between the two of them without seeing them.