All the other T5 tubes and kits that we carry emit light at 6400 degrees Kelvin, or 6400K. However, 2700 degrees Kelvin is considered "warm white" light. It's the light range that plants use for bud and flower development. Due to popular demand, these lower Kelvin T5 tubes are now available in three sizes. They will work with all the T5 fixtures and wiring that we offer. Just swap out the tubes and switch them on. 2700K T5 tubes are useful for inducing flowering in all indoor fruits, vegetables, and houseplants, and should be suspended no more than 30cm (12") above the plants.