The recommended PSU is 12VDC 1.25A, but you could use one of 12VDC 1A or 12VDC 1.5A without issues. It's important that the output voltage is in the range of 7V to 15V. The output current recommended is 1.25A. If the power supply has an output current higher than 1.25A it's ok, but if the output current is lower, the board or the complete circuit might not work if it demands more current than the one provided by the PSU. An output current of 1A might not cause any issues if you power the board and a small circuit, but if you have problems with it then I recommend you to use the one of 12VDC 1.5A.