Rule 500 The Rule 500 offers many design features while keeping size and cost to a minimum. Especially popular on smaller craft, Rule 500 pumps are unmatched in pumping power and longevity. 3/4 (19mm) discharge outlet. 12 Volts DC unless noted. Features: Computerized operation - no floats switch required Fully Submersible Easy clean snap lock strainer Silent and vibrationless operation Anti-airlock protection Compact, efficient long life motor Ignition protected No burn-out when run dry Rust and Corrosion protection Used by leading boatbuilders worldwide marine grade blocked wiring