RocFly Surface Pro 3 Charger/adapter 12V/2.58A Replacement Charger AC Plug Desktop Adapter Power Supply for Microsoft Surface Pro 3 Intel Core i5 i7 Tablet Accessories (Desktop Adapter Power) Designed exclusively for Surface Pro 3 only ( can't fit for pro4 and surface book) I/C Chip technology prevents your tablet's battery overcharging. output:12V 2.58A 36W Easy to carry around, on trip and travel. the 36W Power Supply quickly recharges the battery.