Nikki Idd grabs an energy shield.

An energy shield was a type of droid inhibitor that came in the form of a small rectangular box in the shape of a book. When a droid overloaded, the shield could be inserted into its body, averting the overload and reducing the droid to its basic functions.

If the shield was removed from the droid before repairs had been done, the overload would kick in immediately, proceeding where it had left off.

Nikki Idd once inserted an energy shield in R2-D2 to prevent him overloading in her face. It was later removed by C-3PO to create a diversion for Vik Idd.