Trust it, there are only two things in the power bank, one is the control chip, and the other is the battery core. The battery core is very cheap, but the chip is expensive. You need to buy each company’s fast charging patent and use a special chip. You have to pay money for it and the agreement. No-name power bank does not support fast charging. You don’t have to spend money to buy a patent. It is naturally cheaper. The disadvantage is that it charges slowly.