For MP3 players & other devices that get their power through USB (Universal Serial Bus) Plug your device&s USB (Universal Serial Bus) cable in & charge from almost any vehicle&s 12 volt accessory outlet with this low-profile micro form-factor Power Jolt Works in your vehicle&s 12 volt power outlet Charge 2 USB (Universal Serial Bus) devices at the same time Smart Fuse circuit-breaker protection means no fuses to replace Super-compact form factor 5 watts per port (5 volts 1 amp)