500ft. Spool of 18 Gauge Black 1015 MTW Hookup Wire. Multifunctional 18 gauge wire for use in RV, automotive, truck, trailer and marine wiring applications as well as high voltage uses such as in control cabinets, internal appliance wiring, and machine tools. PVC insulation with a Nominal outside diameter of 0.112''. Meets the following specifications: UL, CSA, MTW, TEW, AWM, 1015, 1230, and 1345. RoHS compliant. Maximum temperature rating of 221°F (105°C). Maximum voltage of 600 volts. Made in the USA.