Static electrons can sit on the surface of tables and floors. This can cause them to hold a positive or negative charge. The charge can then accumulate on objects in a workplace with greater mass if those items are electrically isolated from each other.
Insulating materials like wood tables and wool carpets are known to accumulate charge on them.
When we go to handle electronics we want to make sure tables and floors are not electrically isolated, but instead electrically bonded. Bonding allows those static electrons to discharge from tables and floors into the ground beneath the building they are in. The most common way to “ground” tables and floors is to connect them to an electrical outlet.
These mats are normally used for covering table tops, tray liner, or as “runner” for the length of an assembly line.
The borderline between conductive and static dissipative is 1 million ohms per square. This is also referred to as 1 meg ohm. It is 1 x 106 ohms / square.
The active ingredient used in mats to make them conductive is carbon. Since carbon is black you can easily distinguish its presence from static dissipative material in the mat.