The manual shutoff is meant for emergencies only. In the event you are unable to use the Flo by Moen app to turn your water on or off, you may use the green knob on your Flo by Moen device. Using the supplied hex key, insert it into the hex cutout on the knob, push down all the way, and turn for one quarter turn (clockwise or counterclockwise) to the open or closed position. The valve status light will indicate a solid green LED when it is in the open position, and solid red when it is in the closed position. The knob must be completely pressed down before turning. Failing to do so risks permanent damage to the Flo by Moen device.
You can also use the Flo by Moen app to open and close your valve.