You don’t need to turn off the device, you could just place the device in the charging box and recharge them again when you don’t want to use them.
While if you are not taking the charging box with you, you could turn off the devices to save powder. Please go to Petfon APP, click "Devices" → "Controller/Tracker" → "Shutdown". The power consumption would be much less in shutdown mode.
For controller, you could turn it back on by placing it back into the charging box till it light up, or simply press ring button on the controller.
For tracker, you could only turn it on by placing it back into the charging box.