This is an approximately 650 foot spool of 16 gauge, UL1430 hook-up wire. The inner conductor consists of 19 strands of 29 AWG copper wire, equivalent to 16 AWG in total. The irradiated, cross-linked PVC insulation is blue in color, and provides a great resistance to chemicals, oils, and heat (e.g. the tip of a soldering iron). This hook-up wire is suitable for any general UL1430 application where durability and flexibility are required.