The Ultra Sun® High Pressure Sodium (HPS) lamps have a Kelvin temperature rating of 2000° K which is ideal for the fruiting and flowering stages of plants. It is also an excellent lamp for full-term plant growth. These lamps have been specifically engineered for horticulture applications. Ultra Sun® lamps are high quality, feature robust construction and have excellent reliability at an economical price. . Available online and in-store.