This sensor plugs into your FMM and, using reflected infrared light, will signal your Apex when it changes state from being wet to dry or dry to wet. This sensor can be used for constructing your own ATO (auto-top-off), as a high-level warning sensor in your sump, water storage level sensor, and much more. The sensors can be mounted on any type of reservoir that has up to 1/4″ thick walls.

• Compatible with Neptune FMM Module
• Magnet mounts to walls up to 1/4″ thick
• Can be mounted vertical or horizontal