For a flagship phone charger, the Xiaomi 120W Power Adapter offers one of the fastest charging rates up to 120W. By supporting Qualcomm Quick Charge 5/4+, this charger is able to support more than 100W charging speeds over the USB Type-A connector.
Qualcomm Quick Charge 5 also allows the Xiaomi 120W Power Adapter to support rapid charging using USB Power Delivery 3.0, PPS (Programmable Power Supply) and Qualcomm Quick Charge 4+ technology over the USB Type-C interface.
The Xiaomi 120W Power Adapter came shipped with the Xiaomi Mi 10 Ultra to keep the phone charged using 15 watts (5 volts @ 3 amps), 27 watts (9 volts @ 3 amps), 66 watts (11 volts @ 6 amps) and 120 watts (20 volts @ 6 amps) power profiles. Interestingly this charger depends on the AC input voltage to determine how much power it can deliver. For example, you can only get up to 120W in China or other countries that support 220V using this charger. If you use this charger in the US at 120V, you will only get max of 96W (20V@4.8A). This is quite unusual since the output power is usually independent of AC power.
Note Qualcomm Quick Charge 5 (QC5) support for up to 120W would apply for phones that support QC5, however this has yet to be seen on any QC5 enabled phones.
For fastest charging, make sure to use the supplied USB Type-A to Type-C cable accessory to connect both phone and charger.