First of all, fit is not a fast charging port, many people think that it is fast to charge with this port, so it is mistaken for a fast charging port, but in fact it is different from fast charging.
Secondly, fit means that the smart phone detects the internal charge management, and then outputs the most appropriate maximum current, so that our mobile phone can charge faster, which we should not make a mistake.
fit is the blue USB interface 18W fast charge, two lightning 10W, of course, your phone to support 18W fast charge and above.