To activate the switch, the finger must be positioned on the correct half of the button. This task can also be done using two fingers.
To do a rhythmic alternating movement, selectivity is required in calling on the two fingers to flex in succession.

Inserting a plug in a socket is a task that calls for attention,  coordination and evaluation of the force to do so safely. The patient must grip the two elements firmly in their hands and  connect them to one another.