Little Powerful Giant
I liked the idea when I first saw this product. I ordered and started to power up the Disney Up house and so far, I'm happy with the result. It should contain two CR2025 batteries and I don't know how long they will continue to lighten up my Disney Up set.
Due to its size, it's light and easy to hide somewhere compared to other powering solutions.
I think this unit is suitable to power up relatively smaller sets.
Oh, and don't forget to buy a connecting cable with this unit because sets are coming with a USB power cable, which cannot be used with this power brick.