Growers Choice DE 600W HPS 2KThe Grower's Choice 2K bulb is the optimal choice for blooming plants. Though the 2K HPS can be used in all stages of growth, it contains high concentrations of red and yellow light in it's spectral output, which mimics the natural color of sunlight in the fall, making it best for flowering periods. Outputs UV spectra for enhanced resin production 5% degradation rate at 10,000 hours High quality quartz glass for consistent spectral output and PAR