25GBP is a very good price for such capacity from a decent (supposedly) brand, it's actually below 20gbp on amazon.co.uk, but then, amazon charge you for delivery for anything under 30 quid these days, so.
However, this device is significantly inferior to a similar anker zolo 20K charger:
- it is over 100 g. heavier (anker is already heavy at 370g
- it charges MUCH slower, 6hrs vs around 3hrs
- it recharges PROBABLY at 20W max, because if it recharged at higher rate, they would have shouted 30W!!! - as anker are doing.

Both ugreen and anker are bulky and the angle of that photo with a joyful owner of a brick is not accidental, more of an angle and you'd notice how thick it is, around twice as thick as a mobile. But it's a clever tactics to put two chargers into one package. Basically, if you had one, if it breaks under warranty, they have to replace the whole unit. But if one of the two inside breaks down, the other one still works, you're unlikely to return it and the one left will take you out of the warranty, win for them.
You think I'm paranoid, you haven't worked in the industry, bottom line is the king...