SJE SignalMaster®10ft Mechanically-Activated, Narrow-Angle Control Switch
The 1011678 is a narrow angle float switch. That means that the float switch does not have to raise up very high to trigger the switch.
This switch is most often entrusted to control an alarm circuit, because this switch is rated for a relatively low number of amps. The fact that this is a narrow angle float switch means that it would trigger the alarm before a wide-angle float switch. Meaning, you will be notified sooner if a problem is detected.
The 1011678 is a normally open float switch. This makes it ideal to detect a high-water level. Whenever the water level is low, the float switch will be open. Whenever the water level is too high, the switch will close and indicate to the control panel that the alarm should be activated.