Cat and Mouse type is particularly suited to indicating contained liquid levels when viewed from long distances, e.g. provides indication at 1:1 ratio on a large vertical scale board fixed to a tank side, activated by means an internal float via a wire and pulley system. A tank on a tower installation regularly employs this method.
However it requires the provision of a small hole in the tank roof for float wire access and if the gap provided between wire circumference and hole diameter is greater than 0.65 mm the unit is not suitable for wholesome water tanks.
A further disadvantage, which requires getting used to, the indicating pointer has a reverse action. When the tank is full the indicator is at its lowest point and when empty its at its highest.
Also Read: Sight Glass Level Indicator