Question

what is this on the bottom right? * power button stitch selector bobbin hand wheel

Explanation:

The image shows a sewing - machine - like device. The bottom - right component is a power button, which is typically used to turn the device on or off. Other options like stitch selector (usually a dial for stitch patterns), bobbin (a part for holding thread inside, not in that location), and hand wheel (a larger circular component for manual operation, not here) can be ruled out.

Answer:

power button