S O Cord - 600v 10 Ga x 4 ConductorsSold in sets of 250 The "S" in "SO" means "stranded" or "service wire." Cables so designated are suited for heavy duty industrial tasks requiring 600 volts. The "stranded" refers to the cable's core being composed of multiple strands of conductive materials instead of a solid core. The "O" means that the coating on the outside of the power cable is oil resistant; cables with "O" in their designation can safely be used in environments in which they