2-flat-pin plug 110V input voltage / 9VDC 1A output voltage For use with Arduino Uno, Mega and MB102 Power supply boards Connector size: 5.5 x 2.1mm with Center Tip positive, sleeve is negative These adapters do not work for guitar pedals or label makers which require negative tip power adapters High quality switching 'wall wart' AC to DC 9V 1000mA wall power supply manufactured specifically for Electronics. The output is Center/Tip positive 5.5mmx2.1mm connector. These are switch mode power supplies which mean the output is regulated to 9V and the capable output current is much higher (1000mA!). For use with Arduino Uno, Mega and MB102 Power supply boards. These will power most projects that don't require more than 1000mA of current. Dimensions: 2.91 in x 1.57 in x 1.06 in (7.40 cm x 4.00 cm x 2.70 cm) Weight: 2.54 oz (72 g),