Pacer Black 18 AWG Primary Wire - 500 [WUL18BK-500]Black 18 AWG Primary Wire 500' Pacer's marine wire is designed to handle the harshest marine environments. It is manufactured to meet and exceed the most stringent specifications. This 18 AWG marine wire is constructed in the USA to achieve the highest level of quality. Built from Type III class K tinned copper, this wire offers excellent flexibility. The tinned copper also resists corrosion adding to the life of the wire. What about the insulation?