The Neptune Apex IO Breakout Box is a versatile accessory for saltwater aquarium enthusiasts who want to expand their system’s functionality. It connects external switches and I/O inputs to your Apex AquaController, allowing you to monitor float switches, push buttons, leak detectors, and more without the need for soldering or special tools. The breakout box supports up to six digital inputs depending on your controller model (2 for AC3, 4 for AC3 Pro, and 6 for PX1000), providing flexibility in monitoring various aspects of your aquarium setup.