Specifications for AC-adapter to an old My Book?

I have an old My Book (white color), but I have lost my AC adapter. What are the specifications for the AC-adapter? I know it´s 12 volt DC, but what amperage is it??

Nope … it’s 12 Volts AC (Alternating Current)

It’s AC Switching so it can be used worldwide supporting Input Voltages between 100~240V

Anyways … the My Books use a

12 Volts / 1.5 Amps / 18 Watts / AC Switching Adapter

Power Adapters for WD Products

12V AC ?
All My Book drives I know are using an external switchng power adapter from 220-110V AC to 12V DC. I’ve never seen a white edition drive but I find strange that the AC->DC section is on the main board instead of external power supply.
On the link I see only the voltage/courrent specs withouth the kind of output voltage ( AC or DC )

I have two white My Book with blue rings and they both use:
APD (Asian Power Devices)
AC input 100-240V
DC output 12V 4,0A (48W)

What is the polarity of the 12 DC? Centre + ?

What is the polarity of the 12 DC? Centre + ?