opening it has 2 options inside to regulate power. no idea why has a fan inside all is a big alluminium with 2 mosfets on it. Fan is useless just to make noise. the output has a 20amp fuse when is 4amp charger that need to be changed. inside ground cable is connected to colored alluminium, I removed screw and remove paint to have a normal grounding.
with the great metal case the temperature during charging stays low. the fan is not that silent. the only complain: the specs are not correct. It charges around 3.3a. there are cheaper 4.5amps chargers (rated at 5a) but they get quiet hot. the shipping was long because package was held in belgium customs. need to pay 30 euro extra and 21% of the payed price on the product inclusive shipping cost