This DC power adapter offers the Raspberry Pi a power supply of 5.0V @3.1A.  This is well within tolerance for Micro-USB, and it gives the best stability for most applications.

The recommended and easiest way to power the Raspberry Pi is s via the Micro USB port on the side of the unit. The recommended input voltage is 5V, and the recommended input current is 2A. 

However, this DC power adapter offers 5.0V @3.1A. The reason for increasing the power slightly is to negate any voltage drop caused by excessive current draw.

Note: This item does not include the cable.

Package Includes:

1 X DC Power Adapter (5V/3.5A) 

Technical Specifications: 

• Micro USB Connector
• Short circuit, over-current, and over-voltage protection
• 50,000 Hour MTBF
• Output Voltage: 5.0V
• Minimum Load Current: 0A; Nominal Load Current: 3.5A
• Nominal Power: 15.5 W
• Efficiency: 80.86%
• Input Frequency: 47-63Hz
• Input Voltage Range: 0-264VAC
• Operating Temp: 0 °C to 40 °C
• Storage Temp: 0 °C to 60 °C