Why to buy Apple USB-C Digital HDMI Multiport Adapter MJ1K2AM/A - White :
Plug and Play
The Apple adapter allows you to mirror your MacBook display to your HDMI-enabled TV or display in up to 1080p at 60Hz or UHD (3840x2160) at 30Hz. It also outputs video content like movies and captured video. Just simply connect the adapter to the USB-C port on your MacBook and then to your TV or projector via an HDMI cable (sold separately).
Charge and Sync
Use the standard USB port to connect devices such as your flash drive or camera or a USB cable for syncing and charging your iPhone, iPad, or iPod. You can also connect a charging cable to the USB-C port to charge your MacBook.