Rocker

A heavier on/off for power, mains and arming: a cap that pivots in a black bezel, printed | and O.

Press it: the | half sinks into the bezel and the O half rises toward the lamp.

• A checkbox underneath, so it is reached with Tab and toggled with Space. Name it with a wrapping label or aria-label.
• The | and O marks are the IEC 60417 symbols for on and off; the words beside it still say what it powers.