Absolutely, we have had ours mounted on top of our barn about 60 yards (120 feet ) and it works like a champ. Good product, very accurate. 

To extend the CO detector's working time, the backlight will turn off when there is no operation or alarm signal, but the detector still continue detecting CO per 2s. The audible alarm will sound ""di"" every minute when battery is low power. 

manual says long press - and O at the same time 

After the mobile phone and the device are successfully connected, as long as the device is in the WiFi area where you are connected, your mobile phone can remotely view the device data through the APP as long as it is connected to the Internet. Please pay attention to ensure that you are using 2.4GHz WiFi when connecting, and the WiFi area where the device is located has a strong signal to avoid accidental disconnection due to weak signal. Hope this information is helpful to you. 

Yes, easily.