Gavita horticultural High Pressure Sodium (HPS) lamp with high output and extreme long light maintenance. Change once a year for best results. Initial PPF: 1950 µmol s-1. Light maintenance 5000 hrs: >96%. Color temperature is 2100° K and the lamp base is K12 x 30s. Suitable for High Frequency Gavita Pro 1000 Watt ballasts (Pro-line). The jacket of this double ended lamp is made from quartz glass. Do not handle with bare hands. Oil from your hands can damage the lamp.