Verilux 18 inch 15 watt Fluorescent (T-8) Tube Full Spectrum 6,280K (best full spectrum lamp we offer) Verilux is engineered to reproduce all the colors and balance of natural light. Verilux's extensive line of full spectrum fluorescent tubes feature a stable, custom blend of rare phosphors that create bright, balanced full spectrum light. Used by dentists, artists, aviaries, zoos and last but not least the horticulturalists. In our testing, we have found that the phosphors used in these lamps out last those of other brands. Yes, other manufactures make lamps that produce basically the same light. However, the real question is: How long does the quality light last? Some phosphors loose their ability to be stable in as little as two weeks! Without comparison lamps burning along side each other your eyes will not reveal it the color shift. Stay with quality. Purchase Verilux.