The Wall Adapter Power Supply 7.5VDC 1A is not a common adapter. 7.5 volts is the perfect voltage for many projects.
Specifications
Model: GP301U-750-100
Output: DC2.1 (Arduino Power Jack Compatible)
Input: 100-240V AC ~ 50/60Hz 0.3A
Output: 7.5V 1A DC
American standard connector
Dimensions: 42x66x34 mm (1.65x2.60x1.34")
UL certificated