This Dual HDMI USB C Adapter ONLY work with those devices that the USB Type C Port supports video output or DP Alt Mode.Not for all USB C laptop.
Before you purchase it, Please Attetion:
1.Please check if your laptop owns a USB Type-c Thunderbolt 3 port and support DisplayPort Alternate Mode.
2.On Mac devices, ONLY support Mirror Mode, CAN NOT extend two different Screen, due to Mac OS limitation.

Dual Video Resolution Configurations:
3840x2160@60Hz = 1 display / 3840x2160@30Hz = 2 displays / 2560x1440@60Hz = 2 displays / 1920x1080@60Hz = 2 displays
Please Noted: The final resolution of HDMI output depends on your host devices, (Only when your devices support 4K resolution, the video output will be 4K).

Operating system supported modes:
Mac OS ONLY Support Mirror Mode
Mirror Mode:A-A/AA
( 3 Screens' image will be the same.)
Mirror Mode:A-B/BB
( 2 monitors' image will be the same.)
Please Noted:
Does not support 2 external displays show different images for Apple computers in extend mode.
Support Windows 10 OS
Mirror Mode:A-A/AA
( 3 Screens' image will be the same.)
Extend Mode: A-B/BB/BC
( 2monitors' image can be same or different.)
Please Noted:
For different modes if you are not clear how to setting, we can help you.
Important Noted
For Mac OS it support Mirror mode (AAA), and Extend mode (ABB)
For Windows OS it support Mirror mode (AAA), Extend mode (ABB), and Extend mode (ABC)
Please Noted:
For Apple device, it doesn't support extend 3 different screens.
Support Android OS
Mirror Mode:A-A/AA
( 3 Screens' image will be the same.)