Activate these switches with two hands, reducing the risk of accidental equipment start up. A complete system requires a switch and a safety relay. Switches have an emergency stop push-button to immediately cut power. They are rated IP65 for protection from low-pressure washdowns. Safety relays control the switches when you push the two buttons within 0.5 seconds of each other. Self-monitoring circuitry shuts down the entire system until repaired if any part of it fails. These relays run on 24V DC but can run on 120V AC with a power supply (not included).