Guardian Technologies 7001 Tailgate Alert System for Truck Beds with Tonneau Covers, Fits All Makes and Models Don't lose your expensive possessions because your tailgate was left down The tailgate system contains only 3 components that are securely Affixed to the inside of the truck bed and the outer edge of the truck. Installation only takes a few moments Within several seconds of the tailgate being opened a Red LED light begins to flash. When aligned with the driver's mirror this flash can be easily detected before driving away with gear unsecured System easily runs off 2 AA batteries, included. The long lasting LED bulb flashes yellow when it's time to change the batteries Fits all trucks including Ford, Chevy, GMC, Ram and Toyota. The tailgate system has the option to be permanently attached to your vehicle with screws, included