Conductors: Bare soft annealed copper, Class B, 7-strand concentric per ASTM B-8. Insulation: Flame-retardant Okoseal® (PVC) per UL 13 and UL 2250, 15 mils nominal thickness, 105°C temperature rating. Conductor Identification: Pigmented black and white in pairs, black, red and white in triads. Assembly: Pair or triad assembled with left-hand lay.