Extender does not have a ON/OFF switch and aside from removing the battery it isn’t possible to power cycle the device. In the unlikely event that your Extender freezes up and you have problems with getting it to operate correctly, please first contact online support.
If support is not able to resolve the issue, they may suggest that you perform a hardware reset. Located on the rear of the Extender is a small hole which sits above a hardware reset switch. This is covered over by the the sticker pictured above. You can reach this by pulling back the sticker to expose the hole as shown and use a safety pin to reach the button below. This will cause the microcontroller to reset and go to sleep.