What is aluminum foil on doorknob?

Aluminum foil on doorknob is a common method used for protection against static shocks. The foil is wrapped around the doorknob in such a way that it provides a conductive path for any static charge to dissipate harmlessly. It is often used in areas where there is a high risk of electrostatic discharge, such as clean rooms, laboratories, and server rooms. The foil can also be used to protect against radio frequency interference (RFI) and electromagnetic interference (EMI) by shielding the doorknob from these signals. Overall, aluminum foil on doorknob is a simple and effective solution for preventing damage to sensitive electronic equipment and preventing unwanted static shocks.