Dual ports allows you charge your Surface devices and USB devices simultaneously. Compatibility: Microsoft Surface pro7/6/5/4/3, Surface Laptop1/2/3, Sruface Book1, Surface Go1/2. WITH USB QUICK CHARGE: USB 5V 2.1A car charger fast recharges for devices such as your phone or Pad at the same time Specification: input DC 12-24V/3.5A (MAX); output DC 12V/2.58A & DC 5V/2.1A (USB) SERVICE: We promise you a quick response and a nice solution if you have more details about your problem. Exactly worry-free for you