Type THHN insulation, rated 90 degrees Celsius, 600 volt. Gray PVC jacket. For applications of direct burial, dwellings not exceeding 3 floors above grade, underground feeder to outdoor lighting or apparatus, exposed or concealed wiring in damp, moist, wet, dry, and corrosive locations, general branch circuit wiring and new wiring or replacement wiring. Flame retardant, moisture, fungus, and corrosion resistant. Sunlight resistant jacket. JC-30B Federal specification, ASTM B-3, ASTM B-8 and NY state DOS 1