A:Answer Hi Brian, Thank you very much for reaching out with your question. The "LOC" is a safety feature for locking of the controls to avoid accidental changing of temperature or turning off during use, given the proximity of the buttons to your finger positions while brushing.
Pushing the power button 3 times will turn the unit to the "OFF" position. In addition, after 30 minutes the unit turns off both the heating and ionic features, though we always recommend unplugging for additional safety.
Additionally, if you press the power button twice and then on the third time hold it down, it unlocks and the unit will turn off.
We hope you find this helpful and if there is anything else we can do for you, please don't hesitate to let us know.
Sincerely,
Wild Willies