Xiemin Portable Power Adapter Charger Charging Cable for Microsoft Surface Pro 3 12 Inch Tablet (Pro 3 Charging Cable) Fits for Microsoft Surface Pro 3 12 Inch Tablet I/C Chip technology prevents your tablet's battery overcharging. It is convenient to charge for your pro 3 tablet by mobile power supply. Interface: 5.5mm(outer diameter)*2.1mm(inter diameter) NOTE: ONLY for 12V 2.5A mobile power supply!!!