The Rule ECO-Switch is an ecologically sound automatic bilge pump control switch. Featuring a non-mercury design, the pump operates with simple air pressure. As water rises in the bilge, air rises in the air tube that is attached to the switch. The air pressure activates the switch which controls your pump. All wiring is out of the water, and there are no submerged electrical connections at all. Offering complete reliability and outstanding performance, the Rule ECO-Switch offers a viable alternative to traditional float switches. For pumps drawing up to 20 amps.