It's a standing dock which helps you use the tablet in a more comfortable way. Support New iPad Pro, Samsung Galaxy Tab S4 S5 S6, Surface Go/Pro 7/Pro X, 2-in-1 Pads (Dell/HP/Lenovo/etc) that support USB-C DP Alt Mode.

This is an unboxing video of D42 standing dock 

CB-D42 have 2x USB 3.0 ports, Micro SD / SD dual card readers, 1x HDMI port, 1x USB-C charging port, and 1x 3.5mm Audio port

The nice  unboxing video by @Adrian Tech on YouTube.

The video link https://www.youtube.com/watch?v=NHJzf7qm3pE