The MX keys and MX Master 3 mouse are both excellent individually and can be used to switch between multiple computers. Switching both between computers is however unfeasible in practice because it requires one button press on the keyboard and a further two button presses of a tiny button on the underside of the mouse. This is unacceptable and it should be possible to switch both with a key press on the keyboard. I realise that Flow software is available, but I'm sure that you can understand that it cannot be installed on a client's or employer's laptop because they are locked down and authorisation will not be granted for its installation.