The base is a weighted flanged base that nicely holds the mug and heater.
Inside is just a pass-through from the power supply to the base.
Note that ROTATION counts here -- the mug display has to face away from the power socket to energize.
The AC Adapter is 120-240v AC (travel-friendly), and puts out 19V at 3.42A.
The mug, surprisingly, will draw over 3.5A near the end of boil. I've seen it pull as high as 13 Amps! So be careful what you use for a power supply. Milwaukee M18 batteries work great, if you're comfortable with the unorthodox.
These extra bases are a great to have! It’s nice to have a base station for home and another one for work. I’ll probably end up picking up at least one more for my home office. The battery is great for travel however it’s extremely convenient just to be able to plug in as needed without worrying about using up the battery pack. Thanks for making these available for separate purchase.