The Neptune Systems Optical Sensor with Magnetic Mount is an optical water sensor suitable for the FMM. This sensor plugs into your FMM and will use reflecting infrared light to signal your Apex when it changes state from wet to dry or dry to wet. This sensor can be used to create your own ATO (auto-top-off), such as a high-level warning sensor in your sump, water storage level sensor, and much more. The sensors can be mounted in custom brackets or through a hole in a tank.

*Must be connected to the FMM module

• Included are a fastening nut and silicone washer
• Connection plug: jack plug
• Length of cable: 3m