Official Raspberry Pi Universal Power Supply 2.5A 5.1V Micro USB B 1.5m Cable

From the shop's description

This is Official microUSB Power Supply Unit from Raspberry Pi Foundation. The official and recommended universal micro USB power supply for Raspberry Pi. We’ve tested this supply in all kinds of situations, and it’s as solid as a rock; it’ll keep feeding your Pi the steady 2.5A it needs for proper performance. There are also four interchangeable mains adaptors — you can use it in the UK, Europe, Australia and the United States. Features: 1.5m wire length Interchangeable heads for different countries Short circuit, over current and over voltage protection 5.1V output, 2.5A max output