Qi-infinity8482; 12v 2.5a Dc Connector Portable Charging Cable for Microsoft Surface Pro3 12 Inch Tablet Pc DC charging cable for Microsoft Surface Pro 3 that is compatible with our Powergrid (34200mAh) and Powerplant (52,800mAh) models only. Please note that you need to set voltage at 12V before charging your Surface Pro otherwise your device will not charge. High speed charging cable with LED light, tinned copper contacts and Electromagnetic shielding Specially designed and tested for 34,200mAh Powergrid and 52,400 mAh Powerplant NOTE: ONLY for 12V 2.5A mobile power supply!!! No USB port or AC power supply!