myVolts Ripcord USB to 3V DC power cable is compatible with the Sony AC-ET305K, AC-ES305, AC-ES305K and lets you power the device from a USB port. Works with any USB port - laptop, phone charger, desktop PC, or even a mobile USB battery! It takes the 5V from a USB port and turns it into the 3V and amperage the Sony AC-ET305K, AC-ES305, AC-ES305K PSU part needs. .
