Since most ESD is generated by movement, grounding the biggest source of activity that generates electric charges, people, is an essential element of ESD prevention. Luckily the human body is a good conductor in the world of ESD, with a resistance between 1-2 megohms. To prevent a person from picking up a static charge, a wrist strap is connected to ground with a 1-10 megohm resistance. This resistance slows the discharge rate during an ESD event and protects the user if they accidentally touch an energized circuit, such as household or mains wiring. Real-time static monitoring stations are available provide audible and visual indicators for wrist strap users to ensure that they are properly grounded at all times. Heel straps are also available for ESD protection, which do not tie users down to a single point in the laboratory but they require conductive floors, such as bare concrete, conductive wax, or special static dissipative flooring to work properly.