Yakamoz DC12V External Power Bank Charger Charging Cable Adapter for Microsoft Surface RT Surface Pro/ Pro 2 with Free Lovely Anti Dust Plug Fit for Microsoft Surface RT & Microsoft Surface Pro & Microsoft Surface Pro 2 This cable allows you to connect your external power bank with 12V output to the latest Microsoft Surface Tablet Suitable for DC plug size: 5.5*2.5mm or 5.5*2.1mm Length: Approx 4 ft PLS NOTE: This cable requires external power bank output DC12V 2A for Microsoft Surface RT and output DC12V 3.6A for Microsoft Surface Pro