On Mac devices, ONLY Mirror Mode, CAN NOT extend two different Screen, due to Mac OS limitation; Connect device with USB Type C (tunderbolt 3) port to two external monitors with 4K HDMI output; You can enjoy movies,games with your families on external ultra HD big screen; Windows OS supports both SST and MST mode, if you not sure how to setting, please contact us, or download the user guide in Product information->Product information. ?Wide Compatibility? ??(Attention: It is necessary to confirm that your host device supports video output or DP Alt Mode, and you can normally see the DP-logo next to the port if this is the case, NOT for all USB-C port laptop, such as this adapter CANNOT work with HP Pavilion/HP EliteBook/Lenovo IdeaPad…).This HDMI Reader works well with Thunderbolt 3 compatible devices,such as MacBook/MacBook Pro2020 2019 2018 2017,MacBook Air2020-2018,iPad Pro 2018 ,Dell XPS13/15,Samsung Galaxy S9/S9+,etc ?Vivid 3D Effect Video Sync? This usb c to hdmi adapter resolution up to 4K(3840X2160P@60HZ), dual monitor with HDMI at 3840×2160@30Hz; Dual monitor USB C adapter also support 1440p and 1080p at 60Hz offered by the DisplayPort MST technology; with this high-performance USB-C adapter when you play games the screen without any millisecond delay.?? (Important: ONLY when your devices support 4K resolution, the video output will be 4K,please make sure to use a HDMI 2.0 cable or better.)