Two USB ports to charge both your and your passenger's cell phone, mp3 player or any USB-charged device. To activate your LED USB Port Car Charger Green, plug it into your vehicle lighter port, then plug in your USB cell phone charger. Watch the light glow while it brings your phone back to life. LED Color: Green Dimensions (L x W): 2.85” x 1.3" USB Ports: 2 Does not require batteries, only a vehicle with a functioning lighter port.