None

- Powers off randomly - USB plugs break easily or wear out in under a year with little use.

Kopplen are bad power banks. Very very bad.

I bought this on sale over a year ago. When i got it it wouldnt work at all, so I went in to get an exchange and the new unit worked kind of... I wish i had returned it then. Since owning it for over a year and really tying to give it a try I found it only works for a few seconds to minutes sometimes, so your phonewill maybe get 2 - 4 percent charge before having to turn on the power bank again. I repeat do not buy this brand of power bank, save up and get an anker or something better.