Rachel Ward Bryan Brown Wedding Grower's Choice 3K 500 Watt Single Ended CMH Bulb. Growers Choice 3k CMH lamp utilizes a full phase spectrum that is designed to be used in all stages of growth but optimized for bloom. With a Color Rendering Index of 90 the GC 3k spectrum is very close to natural sunlight but with modest blues, extra red and UV light to serve your plants photosynthetic needs during the flowering phase, increasing yields and resin production. Grower's Choice 3100K 500 Watt SE CMH Bulb Features For use in any standard 500W CMH fixture Produces more PAR per watt than HPS Richest spectrum flowering lamp on the market with a CRI of 90 Optimal for flowering but can be used for Veg as well Promotes higher rate of metabolic activity and resin production through the use of UV and far red spectra Specifications Spectrum: 3100K Lumens Per Watt: 115 Lumens At 100 Hours: 56,000 CRI: 90 Photon Flux: 840 umol s Lifespan: 15,000 hours See the full spec sheet here.