What is the valve on the water tank in the famous modern picture of 2014?

The valve on the 2014 modern famous water tank pin is the water release switch of the water tank. There is also a water tank valve in the heating channel. On the left side of the lower part of the water tank, there is a knob that can be turned to release water. The two straws below are the gearbox. The radiator is almost inside the water tank. The two thick pipes are the upper water pipe joint of the water tank and the lower water pipe joint of the water tank< /p>