9 Volt 1 Amp Power Adapter takes an AC INPUT of 100-240V and gives 9V 1A DC output. The Arduino board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts Details Height (inches) 50 mm Width 100 mm thickness (mil) 10 mm Weight (Oz) 25 g Temperature -10℃ ~ + 50 ℃ Output Voltage 9 V Input Voltage AC 100-240 V Output current 1 A Aging test 100% load aging Storage temperature -20℃～+85℃ Features : Small and Reliable charger. Power Supply with LED indicator.