It is a portable switch dock options available if you're looking for something samller and lighter than Nintendo's official offering.
The portble switch dock has three ports:
USB-C Port: With USB 3.1 Type-C PD fast charging port, its max watt is 31W. It can supports 5V~3A, 9V~3A, 12V~ 2.58A, 15V~ 2.06A, 20V~ 1.55A fast charging.
Noted: Although the maximum output power supported by the official charging head of the switch is 15V 2.6A, the actual input power for charging the switch is only about 15W.
HDMI Port: This Switch TV Docking Station supports 4K@60Hz (Max) HDMI Output. In TV Mode, you can experience games with everyone on the big screen.
Such as: Monitor, TV, projector.
USB 2.0 Port: Link your accessories to your console. It also supply 5V1A power, and you can charge or power up your devices by using this port.