Anti-Static (AS) :
 Resistivity generally between 109 and 1012 ohms per square.
Initial electrostatic charges are suppressed.
May be surface resistive, surface-coated or filled throughout. 　
Static Dissipative (SD) :
Resistivity generally between 106 and 109 ohms per square.
Low or no initial charges -- prevents discharge to from human contact.
May be either surface-coated or filled throughout.
Conductive (CN) :
Resistivity generally between 103 and 106 ohms per square.
No initial charges, provides path for charge to bleed off.
Usually carbon-particle or carbon-fiber filled throughout.