The HD Switch WaterProof LED Relay with Diode Makes Diagnostics a Breeze. HD Switch Integrated an LED Light to Show When the Relay has been Switched. The LED Light Turns On When The Relay is Activated. The LED Light Shows if the Relay is Getting Power and If the Relay is Switching Properly; Making Diagnostics Simple. The HD Switch Relay is IP68 Certified, 100% Sealed and Completely DustProof & WaterProof. This is a Costly Manufacturing Upgrade that Most Aftermarket Relays Do Not Have. Each HD Switch Relay Comes with a Free Packet of Dielectric Grease Used to Coat The Terminals and Protect against Corrosion.