The FCI floating ball continuous level gauge uses the magnet inside the floating ball to change the resistance inside the body rod and the voltage divider circuit composed of a magnetic spring switch with the change of the liquid level, thereby converting the partial pressure signal. This partial pressure signal can be converted into a standard industrial signal of 4-20mA through the level gauge to detect the liquid level The smaller the gap of the magnetic spring switch, the higher the accuracy. This level gauge can also be used in conjunction with other secondary instruments for remote indication. It is a simple principle and highly reliable level indicator.