Rule-A-Matic Bilge Pump Float Switch 35A The Rule-A-Matic Bilge Pump Float Switch is designed for automatic onoff bilge pump control. Rule-A-Matic Plus bilge switches have 14 gauge highly abrasive resistant, marine-grade blocked wire and exclusive moisture-tight seals. All Rule float switches are mercury-free and are tested to over one million cycles. It is recommended that the Rule-A-Matic is installed on a flat surface in the bilge compartment for maximum performance. The Rule-A-Matic Float Sw