The Rule-Mate 1100 Automatic Bilge Pump, Original Code Rule Rm1100B, Is Equipped With An Electronic Sensor That Starts It When The Water Reaches 5 Cm And Automatically Stops When The Water Is Completely Drained. This Sensor Is Defined As A Field Effect, Meaning It Does Not Start The Pump If There Is Oil Present, Thus Ensuring Enironmental Respect.