Aluminium profile, 1 U (width 44.5 mm) with standard ESD connectors.

ESD is the abbreviation for electrostatic discharge, which occurs when two bodies at different electrical potentials come into to contact and their charges equalise.

Electrostatic charges are created when two dissimilar materials are rubbed together or are separated from one another. Examples include: walking on plastic floors, rubbing against synthetic clothing, the displacement of plastic containers, the unrolling of adhesive PVC tapes or the movement of conveyor belts. In modern workspaces static charges can create high static voltages. Charges of above 10 kV are not uncommon. Where air humidity is below 20 %, values of 30 kV have been recorded.