INDOOR SUN 600W/400V HPS PRO HV lamps are designed specifically for professional growers. most powerful HPS (High Pressure Sodium) lamp technology produces a spectrum that is ideal for horticultural applications. With a lamp life of up to 24,000 hours, the INDOOR SUN 600W/400V HPS PRO HV is an excellent choice for growers who demand the highest quality and performance from their lighting system.