in fig 4, we see a third method. this method of connection puts the current-limiting resistors of both the wrist strap and ground cord in series with the resistance of the table mat or covering. since resistances in series are cumulative, it is possible that total resistances to ground could be so high that static-decay time from the person wearing the wrist strap might exceed acceptable time limits.(Note: Mats equipped with studs at both sides are intended for left-or right handed use for the worker's convenience, not formaking series connections; see fig 5.)