An ESD mat is a very important part of an ESD protected area.  ESD mats are designed to eliminate static on its surface and of objects placed upon it.  It does this by having a conductive material embedded within the mat that collects the static and sends it to ground (earth).
All static control mats are not created equally. The ESD mat’s long-term electrical properties are tantamount to successfully controlling an ESD event. Surface resistance is a measurement of how easily an electric charge can travel across a medium, and ESD mats required to have a specific resistance.