This single conductor wire is double insulated with heat and moisture resistant, cross-linked polyethylene insulation, and thermoplastic jacket (Type PV wire, USE-2, RHH, RHW, RHW-2). Rated for direct burial or in conduit and is sunlight resistant flame retardant, and rated for temperatures from -40 to 90C. It meets the 2008 NEC code for use with transformerless inverters. Listed as Type PV Wire, USE-2 600V per UL 854.