Since only one dongle is included with the mouse, but it can also be connected to 3 devices at the same time, it is obvious that the Master 3, like my Master 2S, can also be connected via Bluetooth without a dongle.

I use the concept extensively to control my work PC with my Master S2 mouse and my Craft keyboard, but also my HTPC at the other end of my room if something is playing on YouTube that is too loud when a phone comes in or if I need to do something quickly on my Surface Book 2 that is easier to do with a mouse than with a touch or trackpad.

At the HTCP, with the same mouse and keyboard, it then goes one step further to the Xbox One X where there is a dongle in it so that you can chat faster with the keyboard (mouse also works but I only have Minecraft where it would work).

The dongle is for the 2.4ghz Wifi connection. No dongle is needed for Bluetooth.

What is the Bluetooth dongle for?