This is an example of a fake or look-a-like charger purchased online.
It weighs 25g
The specs claim 5v 1A
at 500mA voltage drops to 4.91, 600mA drops even more to 3v, then at around 700mA it cuts out completely.
No tools required to open it, I could just pull it apart by the pins.
The seperation between the high and low voltage sides is very poor
Hi-voltage side highlighted, most places it's much less than 1mm, this is very dangerous.
Another thing you will notice is it was incredibly filthy inside this thing, how they managed that I have no idea.
And finally what the output actually looks like
1.31v peak-to-peak voltage, very noisy poor output.
This is not suitable for charging a mobile device, you may find the battery gets hot quickly and screen becomes unresponsive when in use.